2021-12-26 last update, 2013-02-02 first day, Robert Jasiek

Go Theory Research

The page lists the research of some important go theory researchers.

Abbreviations
Robert Jasiek's Go Theory Research
Bill Spight's Go Theory Research

Abbreviations

[A] = alternative proof
[C] = invented general major concept
[D] = definition or overview
[G] = general knowledge stated as principle, procedure, method, definition, rule or ruleset; applies to arbitrary values and arbitrary positions of a class
[I] = invention
[T] = theorem and proof; therefore application is always correct
[W] = first or probably first to write down clearly verbal knowledge in English, German or possibly world literature
[b] = book
[m] = message
[p] = paper or webpage

Robert Jasiek's Go Theory Research

Preface
The Most Important Inventions for Players
The Most Important Inventions for Advance of Go Theory
The Most Difficult Inventions
Endgame

Theorems
Other Theory
Definitions
Examples

Tactical Reading and Move Decision
Strategy
Capturing Races
Joseki
Positional Judgement
Ko and Other Restrictions
Life + Death and Scoring
Rules
Shapes
Other Terms

Preface

My 1000 informal or semi-formal principles, of which many are important for go theory and more often correct than those by other writers, and minor definitions, research etc. are not mentioned here. After some preliminary studies, I began serious research in go theory in 1996.

The research is by Robert Jasiek unless other names are stated. Two or more names without attributes are listed in decreasing order of contribution. Names separated by a slash indicate equal contribution.

Outside the lists of most important inventions, bold font denotes the relatively more important research.

Many inventions reveal gaps in earlier common informal knowledge and in teaching by professional players. The "Neutral stone difference" is an example of a simple concept that professional players apply but amateurs often do not apply because it has not been taught by anybody except me, although each new neutral stone too many equals one pass during the middle game.

The two top inventions for players ("Playing simple gotes without follow-ups in decreasing order" and "Timing during the early endgame of playing in a local gote in an environment") are inventions from the view of mathematical research and confirm common informal knowledge. Some other inventions ("Non-existence of local double sente", "Counter-example for always seeking tedomari" and "Counter-examples for always playing a simple gote with one follow-up in an environment of simple gotes without follow-ups in decreasing order of move values") refute common informal knowledge. We cannot trust common informal knowledge but we can trust mathematical theorems.

Difficulty and effort of inventions do not correlate with their importance. It was difficult to prove "Timing during the early endgame of playing in a local gote in an environment" but took me only 20 minutes to prove "Playing simple gotes without follow-ups in decreasing order". Although the proof only needs school mathematics, several go players failed to prove it. I only list mine as "alternative proof" (instead of full "invention") because it expresses taking numbers in decreasing order, for which I could not find a proof but only much research by mathematicians on advanced alternating sums. Please let me know if you find some proof dated before 2021!

Although many simple but important inventions can be made, there are only a few serious researchers in go theory. A reason may be that simple but important theory does not pop up by itself. It requires years, or even many years, of study to see through the fog of less relevant knowledge.

The Most Important Inventions for Players

Playing simple gotes without follow-ups in decreasing order [GA] [b] [like taking numbers in decreasing order]
Timing during the early endgame of playing in a local gote in an environment [IGT] [b]
Verify types of local endgames to determine their correct values. [IGT] [bm] [Robert Jasiek / Bill Spight]
Equivalence of conditions (gote / sente count versus gote / follow-up move value versus sente / follow-up move value versus gote / sente move value) of local endgame with one simple follow-up [IGT] [bm] [proofs Robert Jasiek, conjectures Bill Spight]
Neutral stone difference, neutral-or-dead stone difference [ICGD] [b]
Earliest and latest moments of playing in a local endgame in sente or reverse sente depending on the enironment [IGT] [bm] [Bill Spight, Robert Jasiek]
Several local endgames

Creator starting in the larger local endgame with one follow-up [IGT] [bm] [Robert Jasiek, Bill Spight]
Preventer starting in the larger local endgame with one follow-up [IGT] [bm] [Robert Jasiek, Bill Spight]

Use the principle of extreme difference values to simplify reading for several iterative local endgames. [IG] [b]
Approach plays affecting the score [IGT] [b]
Direct connection, indirect connection [IWGD] [b]
Influence stone difference [ICGD] [b]
Re-definition of two-eye-formation [IGD] [pm]
Definition of stability [ICGD] [b]
Classification of regions [IWG] [b]
Definition of current territory [ICGD] [b] [there was the predecessor Cho Chikun]
Value of a fighting region [ICGD] [b]
Relation between area count and territory count [IG] [b]
Timing during the late endgame at low temperature of playing in a local gote with two simple follow-ups in an environment [IGT] [b]
For a local sente during the early endgame at high temperature, play in the environment [IGT] [b]
Ordinary evaluation of long sequences by the method of making a hypothesis [IG] [b]
Evaluation and choice in a ko exchange [IWG] [b]
Method of comparing two sequences combined with the method of comparing counts during the late endgame in a local endgame with one follow-up in an environment [IGT] [bm] [Robert Jasiek, Bill Spight]
Method of comparing two sequences combined with the method of comparing counts during the late endgame in a local gote with two simple follow-ups in an environment [IGT] [b]
Generalised connection (n-connected) [ICGD] [b]
General definition of thickness [ICGD] [b] (informal and formal versions; simplified types; degrees and evaluation)
General definition of influence [ICGD] [b] (informal and formal versions; degrees and evaluation)
Non-existence of local double sente [IGT] [bm] [Francisco Criado, Robert Jasiek, Bill Spight]
Evaluation of global double sente [IG] [b]
Method of value evaluation of all josekis, except those with global (ko or semeai) fights [ICG] [b]
New Semeai Formula [IG] [b]
Local endgame with gote and sente options in an environment

Timing during the early endgame at high temperature of playing in a local endgame with gote and sente options in an environment [IGT] [b]
Timing during the early endgame at low temperature of the preventer playing in a local endgame with gote and sente options in an environment [IGT] [b]

Ko and dame endgames under area scoring [IWGT] [pm]

The Most Important Inventions for Advance of Go Theory

General definition of ko, regardless of position and ruleset [IGD] [p]
Timing during the early endgame of playing in a local gote in an environment [IGT] [b]
Local endgame with one follow-up in an environment

Timing during the late endgame at low temperature of the creator playing in a local endgame with one follow-up in an environment [IGT] [bm] [Bill Spight, Robert Jasiek]
Timing during the late endgame at low temperature of the preventer playing in a local endgame with one follow-up in an environment [IGT] [b]
Timing during the late endgame at high temperature of the creator playing in a local endgame with one follow-up in an environment [IGT] [b]
Timing during the late endgame at high temperature of the preventer playing in a local endgame with one follow-up in an environment [IGT] [b]
Method of comparing two sequences combined with the method of comparing counts during the late endgame in a local endgame with one follow-up in an environment [IGT] [bm] [Robert Jasiek, Bill Spight]
Equivalence of a) the method of comparing two sequences combined with the method of comparing counts, b) the method of comparing two sequences combined with the method of comparing net profits, and c) the method of applying a principle of playing in a local endgame with one follow-up in an environment during the late endgame [IGT] [b]
For a local sente during the early endgame at high temperature, play in the environment [IGT] [b]

Local gote with two simple follow-ups in an environment

Method of comparing two sequences combined with the method of comparing counts during the late endgame in a local gote with two simple follow-ups in an environment [IGT] [b]
Timing during the late endgame at low temperature of playing in a local gote with two simple follow-ups in an environment [IGT] [b]
Timing during the late endgame at medium temperature with larger follow-up of playing in a local gote with two simple follow-ups in an environment [IGT] [b]
Timing during the late endgame at medium temperature with smaller follow-up of playing in a local gote with two simple follow-ups in an environment [IGT] [b]
Timing during the late endgame at high temperature of playing in a local gote with two simple follow-ups in an environment [IGT] [b]
Equivalence of a) the method of comparing two sequences combined with the method of comparing counts, b) the method of comparing two sequences combined with the method of comparing net profits, and c) the method of applying a principle of playing in a local gote with two simple follow-ups in an environment [IGT] [b]

Several local endgames

Creator starting in the larger local endgame with one follow-up [IGT] [bm] [Robert Jasiek, Bill Spight]
Preventer starting in the larger local endgame with one follow-up [IGT] [bm] [Robert Jasiek, Bill Spight]

Local endgame with gote and sente options in an environment

Timing during the early endgame at low temperature of the preventer playing in a local endgame with gote and sente options in an environment [IGT] [b]
Timing during the early endgame at high temperature of playing in a local endgame with gote and sente options in an environment [IGT] [b]

General definition of thickness [ICGD] [b] (informal and formal versions; degrees and evaluation)
General definition of influence [ICGD] [b] (informal and formal versions; degrees and evaluation)
Capturable-1, local-2, capturable-2 [IGD] [pm]
Alive in Japanese 2003 Rules equals alive in World Amateur Go Championship Rules model [IT] [m] [proof Chris Dams, conjecture Jasiek]
Method of value evaluation of all josekis, except those with global (ko or semeai) fights [ICG] [b]
New Semeai Formula [IG] [b]
Re-definition of strategy, hypothetical-strategy, force, prevent [IWGD] [pm] [there were the predecessors Bernd Gramlich and Robert Pauli and also researchers of mathematics or abstract games]
Equivalence of conditions (gote / sente count versus gote / follow-up move value versus sente / follow-up move value versus gote / sente move value) of local endgame with one simple follow-up [IGT] [bm] [proofs Robert Jasiek, conjectures Bill Spight]
Non-existence of local double sente [IGT] [bm] [Francisco Criado, Robert Jasiek, Bill Spight]
Scoring

For any standard area komi, odd board parity and even seki parity, the winner is the same under area and territory scoring. [IGT] [bm]
For any standard area komi, odd board parity, even seki parity and the territory score 0.5, the winner under territory and area scoring is the player of the last play. [IGT] [bm]

Earliest and latest moments of playing in a local endgame in sente or reverse sente depending on the enironment [IGT] [bm] [Bill Spight, Robert Jasiek]
Generalised connection (n-connected) [ICGD] [b]
General classification and definition of basic-ko types, regardless of position and ruleset [IGD] [p]
Generalised territory (n-territory) [ICGD] [b]
Influence stone difference [ICGD] [b]

The Most Difficult Inventions

Japanese 2003 Rules [IG] [p] [11 months of full-time work after 10 years of preliminary study]
General definition of ko, regardless of position and ruleset [IGD] [p] [~3 months of full-time work after 13.5 years of preliminary study]
Timing during the early endgame of playing in a local gote with two follow-ups and unequal move value in an environment [IGT] [b] [3 weeks of full-time work after 3.5 years of preliminary study]
Timing during the early endgame of playing in a local gote with one follow-up and unequal move value in an environment [IGT] [b] [3 weeks of full-time work after 3.5 years of preliminary study]

Endgame

Theorems

Combinatorial Game Theory

Monotonicity and continuity of enriches scores [GA] [b] [Francisco Criado, Robert Jasiek]
Equal scores in case of large enough temperatures [GA] [b] [Francisco Criado, Robert Jasiek]
Orthodox forecast theorem [GA] [b]

Fundamentals

Playing simple gotes without follow-ups in decreasing order [GA] [b] [like taking numbers in decreasing order]
Equality of move value and gains in a local gote [GA] [b]
Count of a local gote, ordinary ko or ko threat [GA] [b]
Impact of net profit on counts [GA] [b]
Net profit of starting in an ideal environment [GA] [bm]
Maximum net profit of starting in a simple environment [GA] [b]
Error tolerance of two values (gains) taken alternately [IGT] [b]
Bounds of inserting a value in an ideal environment [IGT] [bpm] [Robert Jasiek, Francisco Criado]
Bound of adding a move value to an alternating sum [IGT] [bpm] [Robert Jasiek, Daniel Hu]
Adding two values to an alternating sum [IGT] [bpm] [Daniel Hu, Robert Jasiek]

Evaluation of Local Endgame with One or Two Follow-ups

Equivalence of conditions (gote / sente count versus gote / follow-up move value versus sente / follow-up move value versus gote / sente move value) of local endgame with one simple follow-up [IGT] [bm] [proofs Robert Jasiek, conjectures Bill Spight]
Equivalence of counts and white-counts of local endgame with one simple follow-up [IGT] [b]
Equivalence of move values for Black's and White's value perspectives of local endgame with one simple follow-up [IGT] [b]
Non-existence of local double sente [IGT] [bm] [Francisco Criado, Robert Jasiek, Bill Spight]
Equivalence of tentative move values and counts of local endgame with one or two unsettled sente followers [IGT] [b]

Evaluation of Local Endgame with Gote and Sente Options

Equivalence of conditions (gote / sente count versus gote / sente move value) of local endgame with a player's simple gote and sente options [IGT] [bm] [proofs Robert Jasiek, conjectures Bill Spight]
Equivalence of counts and white-counts of local endgame with a player's simple gote and sente options [IGT] [b]
Equivalence of move values for Black's and White's value perspectives of local endgame with a player's simple gote and sente options [IGT] [b]

Evaluation of Local Endgame with Long Sequences

Method of comparing the opponent's branches, 3-move traversal, evaluation due to reversal [IGT] [bm] [Bill Spight, Robert Jasiek]
Method of comparing the opponent's branches, 4-move sente sequence, determination of counts and move values [IGT] [b]
Method of comparing the opponent's branches, 3-move reverse sente sequence, determination of counts and move values [IGT] [b]
Methods of comparing counts or move values, and their relations [IGT] [b]
Study of the method of making a hypothesis, T-orthodox implies T is at most the gains [IGT] [b] [Francisco Criado, Robert Jasiek]
Study of the method of making a hypothesis, T-orthodox implies the move value is at most the gains [IGT] [b] [Robert Jasiek, Francisco Criado]
Study of the method of making a hypothesis, smaller move value after traversal [IGT] [b]

Early Endgame of Local Gote in an Environment

Timing during the early endgame of playing in a local gote with one follow-up and unequal move value in an environment [IGT] [b]
Timing during the early endgame of playing in a local gote with one follow-up and equal move value in an environment [IGT] [b]
Timing during the early endgame of playing in a local gote with two follow-ups and equal move value in an environment [IGT] [b]
Timing during the early endgame of playing in a local gote with two follow-ups and unequal move value in an environment [IGT] [b]
Timing during the early endgame of playing in a local gote in an environment [IGT] [b]

Late Endgame of Local Endgame with One Follow-up in an Environment

Timing during the late endgame at low temperature of the creator playing in a local endgame with one follow-up in an environment [IGT] [bm] [Bill Spight, Robert Jasiek]
Timing during the late endgame at low temperature of the preventer playing in a local endgame with one follow-up in an environment [IGT] [b]
Timing during the late endgame at high temperature of the creator playing in a local endgame with one follow-up in an environment [IGT] [b]
Timing during the late endgame at high temperature of the preventer playing in a local endgame with one follow-up in an environment [IGT] [b]
Difference of the net profits of Black versus White starting alternating play on an alternating sum [GA] [b]
Method of comparing two sequences combined with the method of comparing counts during the late endgame in a local endgame with one follow-up in an environment [IGT] [bm] [Robert Jasiek, Bill Spight]
Method of comparing two sequences combined with the method of comparing net profits during the late endgame in a local endgame with one follow-up in an environment [IGT] [bm] [Robert Jasiek, Bill Spight]
Equivalence of a) the method of comparing two sequences combined with the method of comparing counts, b) the method of comparing two sequences combined with the method of comparing net profits, and c) the method of applying a principle of playing in a local endgame with one follow-up in an environment during the late endgame [IGT] [b]

Early Endgame of Local Endgame with One Follow-up in an Environment

Timing during the early endgame at low temperature of the creator playing in a local endgame with one follow-up in an environment [IGT] [b]
Timing during the early endgame at low temperature of the preventer playing in a local endgame with one follow-up in an environment [IGT] [b]
Timing during the early endgame at high temperature of playing in a local endgame with one follow-up in an environment [IGT] [b]
For a local sente during the early endgame at high temperature, play in the environment [IGT] [b]

Late Endgame of Local Gote with Two Follow-ups in an Environment

Method of comparing two sequences combined with the method of comparing counts during the late endgame in a local gote with two simple follow-ups in an environment [IGT] [b]
Method of comparing two sequences combined with the method of comparing net profits during the late endgame in a local gote with two simple follow-ups in an environment [IGT] [b]
Timing during the late endgame at low temperature of playing in a local gote with two simple follow-ups in an environment [IGT] [b]
Timing during the late endgame at medium temperature with larger follow-up of playing in a local gote with two simple follow-ups in an environment [IGT] [b]
Timing during the late endgame at medium temperature with smaller follow-up of playing in a local gote with two simple follow-ups in an environment [IGT] [b]
Timing during the late endgame at high temperature of playing in a local gote with two simple follow-ups in an environment [IGT] [b]
Equivalence of a) the method of comparing two sequences combined with the method of comparing counts, b) the method of comparing two sequences combined with the method of comparing net profits, and c) the method of applying a principle of playing in a local gote with two simple follow-ups in an environment [IGT] [b]
Ignored tails during the late endgame in a local gote with two simple follow-ups in an environment [IGT] [b]
Increasing scores of the starting player for a local gote with two simple follow-ups in an environment [IGT] [bpm] [Daniel Hu, Robert Jasiek]
Decreasing scores of the second-moving player for a local gote with two simple follow-ups in an environment [IGT] [bm] [Robert Jasiek, Daniel Hu]

Late Endgame of Local Endgame with Gote and Sente Options in an Environment

Method of comparing three sequences combined with the method of comparing counts during the late endgame of the creator playing in a local endgame with gote and sente options in an environment [IGT] [bm] [Robert Jasiek, Bill Spight]
Method of comparing three sequences combined with the method of comparing counts during the late endgame of the preventer playing in a local endgame with gote and sente options in an environment [IGT] [b]
Timing during the late endgame at low temperature of the creator playing in a local endgame with gote and sente options in an environment [IGT] [bm] [Bill Spight, Robert Jasiek]
Timing during the late endgame at low temperature of the preventer playing in a local endgame with gote and sente options in an environment [IGT] [b]
Timing during the late endgame at high temperature of the creator playing in a local endgame with gote and sente options in an environment [IGT] [b]
Timing during the late endgame at high temperature of the preventer playing in a local endgame with gote and sente options in an environment [IGT] [b]

Early Endgame of Local Endgame with Gote and Sente Options in an Environment

[Bill Spight solves the timing during the early endgame at low temperature of the creator playing in a local endgame with gote and sente options in an environment] [IGT] [bm]
Timing during the early endgame at low temperature of the preventer playing in a local endgame with gote and sente options in an environment [IGT] [b]
Timing during the early endgame at high temperature of playing in a local endgame with gote and sente options in an environment [IGT] [b]

Several Local Endgames

Creator starting in the larger local endgame with one follow-up [IGT] [bm] [Robert Jasiek, Bill Spight]
Preventer starting in the larger local endgame with one follow-up [IGT] [bm] [Robert Jasiek, Bill Spight]
Additional details for playing in the larger local endgame with one follow-up [IGT] [bm] [Bill Spight, Robert Jasiek]

Scoring

Relation between komi, area scores and winners [IGT] [bm]
Relation between area and territory scores [IGT] [bm]
For any standard area komi, odd board parity and even seki parity, the winner is the same under area and territory scoring. [IGT] [bm]
For any standard area komi, odd board parity, even seki parity and the territory score 0.5, the winner under territory and area scoring is the player of the last play. [IGT] [bm]
Approach plays affecting the score [IGT] [b]

Other Theory

Evaluation

Verify types of local endgames to determine their correct values. [IGT] [bm] [Robert Jasiek / Bill Spight]
Types of sequences [IG] [b]
Simplifications of local evaluation [I] [b]
Evaluation of global double sente [IG] [b]
Ordinary evaluation of long sequences by the method of making a hypothesis [IG] [b]
Fast evaluation of long sequences by the method of comparing the opponent's branches [IG] [b] [Bill Spight, Robert Jasiek et al]
Fast evaluation of long sequences by the method of comparing counts [IG] [b]
Fast evaluation of long sequences by the method of comparing move values [IG] [b]
Net profit 0 of a sente sequence [W] [b]
Describing traditional endgame theory as if derived from modern endgame theory [IWG] [b]
Relation between area count and passes [WG] [b]
Relation between area count and territory count [IG] [b]

Strategy

Do not always play in decreasing order of move values but use better theory. [IGT] [bm] [Robert Jasiek, Bill Spight]
Interrupt local sequences in time. [IGT] [bm] [Robert Jasiek / Bill Spight]
Strategy depends on the parity of the number of multiples. [W] [bm]
Strategy depends on the local endgame / ensemble, the environment, its temperature and sometimes its second-largest value. [IGT] [bm] [Robert Jasiek / Bill Spight]
Use the gote move value for the timing during the early endgame of playing in a local gote. [IGT] [b]
[Bill Spight finds use of the sente move value for the timing during the late endgame of playing in a local gote.] [IGT] [bm]
The creator chooses the gote option during the early endgame at high temperature if playing locally in a local endgame with gote and sente options in an environment. [IGT] [b]
Exact theory for local endgames with simple follow-ups serves as an approximation for local endgames with iterative follow-ups. [IGT] [b]
Several local endgames each with one follow-up can be partially simplified by the theory for larger such local endgames. [IGT] [bm]
Application to strategy and positional judgement during the middle game [IGT] [bm] [Bill Spight, Robert Jasiek]
Earliest and latest moments of playing in a local endgame in sente or reverse sente depending on the enironment [IGT] [bm] [Bill Spight, Robert Jasiek]
Use the principle of extreme difference values to simplify reading for several iterative local endgames. [IG] [b]
Translation of relevant combinatorial game theory (including low-level theory and corridors) to go theory. [IGT] [bm] [Robert Jasiek, Bill Spight et al]
Conditions for preserving ko threats [IG] [b]
Evaluation and choice in a ko exchange [IWG] [b]

Definitions

Terms

White-count [ID] [b]
Ideal environment [ID] [bm]
Tail [ID] [b]
Alternating sum [ID] [bm]
Alternating sum of tails [ID] [b]
Alternating sum for medium temperature with larger follow-up [ID] [b]
Alternating sum for medium temperature with smaller follow-up [ID] [b]
Alternating sum for high temperature [ID] [b]
[Daniel Hu defines scores of playing locally after 2I or 2I+1 moves] [ID] [p]
Traversal, traversal sequence [IWD] [b]
Creator [ID] [b]
Preventer [ID] [b]
Gote-sente-difference [ID] [b]
Larger local endgame with one follow-up [ID] [bm]
Standard area komi [ID] [bm]
Local stone difference [ID] [b]
Clarified use of the term net profit [W] [bm]

Value Conditions of Terms

Privilege [WD] [b]
Gain [W] [bm]
Simplifying redefinition of sente count [D] [b]
Simplifying redefinition of move value 0 of settled position [D] [b]

Values of Local Endgames

Tentative gote or sente counts and move values of local endgame with one simple follow-up [ID] [b]
Tentative gote or sente counts and move values of local endgame with two simple follow-ups [ID] [b]
Tentative gote or sente counts and move values of local endgame with a player's simple gote and sente options [ID] [b]
Overview of gote or sente counts and move values of local gote, local sente or ambiguous local endgame with one simple follow-up [ID] [b]
Overview of gote or sente counts and move values of local gote, local sente or ambiguous local endgame with a player's simple gote and sente options [ID] [b]

Types of Local Endgames

[Bill Spight defines the types (local gote, local sente, ambiguous of a local endgame with one simple follow-up.] [ID] [m]
Types (local gote, Black's / White's local sente, local sente, Black's / White's / doubly ambiguous, ambiguous) of local endgame with two simple follow-ups [ID] [b]
Overview on types of local endgames [ID] [b]
Types (local gote, local sente, ambiguous) of local endgame with a player's simple gote and sente options [ID] [b]
Overview of conditions of local gote, local sente or ambiguous local endgame with one simple follow-up from Black's or White's value perspective [ID] [b]
Types (local gote, local sente, ambiguous) of local endgame with a player's simple gote and sente options [ID] [b]
Overview of conditions of local gote, local sente or ambiguous local endgame with a player's simple gote and sente options [ID] [b]

Test Sequences

Test sequences for a local endgame with one follow-up in an environment [ID] [bm] [Bill Spight, Robert Jasiek]
Test sequences for the creator starting in a local endgame with gote and sente options in an environment [ID] [bm] [Bill Spight, Robert Jasiek]
Test sequences for the preventer starting in a local endgame with gote and sente options in an environment [ID] [b]

Examples

Counter-example for always seeking tedomari [I] [b]
Counter-examples for always playing a simple gote with one follow-up in an environment of simple gotes without follow-ups in decreasing order of move values [I] [b]
Rare example of local endgame with a player's simple gote and sente options, late endgame, low temperature, the opponent's correct start in the environment [I] [b]
Counter-example for comparing move values instead of gains to decide traversal [I] [b]
[Francisco Criado shows two rare counter-examples for which the method of making a hypothesis is wrong so thermography is required] [I] [b]

Tactical Reading and Move Decision

Method of regular reading [WG] [b]
Method of test reading [IG] [b]
Method of local Move Selection [WG] [b]
Move choice: 2 methods [WG] [b]
Reduction of a big moyo: 2 methods [WG] [b]

Strategy

General

Re-definition of strategy, hypothetical-strategy, force, prevent [IWGD] [pm] [there were the predecessors Bernd Gramlich and Robert Pauli and also researchers of mathematics or abstract games]
Answer-strategy, answer-force [IGD] [p]
Virtual-force [IGD] [p] [there is a related term by other researchers]
Strategic planning: 4 methods [WG] [b]
Offering a strategic choice [WG] [b]
Use and transformation of influence or thickness [WG] [b]
General fighting strategy [WG] [b]

Strategic Concepts

Generalised connection (n-connected) [ICGD] [b]
Generalised life (n-alive) [GD] [b]. [A related prior concept is 'possible omission number'.]
Generalised territory (n-territory) [ICGD] [b], 1 derived definition (half territory) [ICG] [b]
General definition of influence [ICGD] [b] (informal and formal versions; degrees and evaluation)
General definition of thickness [ICGD] [b] (informal and formal versions; degrees and evaluation)
Influence stone difference [ICGD] [b]
Definition of stability [ICGD] [b]
Territory efficiency [IGD] [b] [prior work by Yang Yilun and possibly others]
Investment [ICGD] [b]
Playing elsewhere: 1 method [IG] [b]
Mobility [IWCG] [b]
Types of fights [WG] [b]
Fighting region [ICGD] [b]
Value of a fighting region [ICGD] [b]
Neutral stone difference, neutral-or-dead stone difference [ICGD] [b]
Potential [WG] [b]
Development [WG] [b]

Capturing Races

New Semeai Formula [IG] [b]
Usual move order [WG] [b]
6 classes of basic capturing races [IG] [b]
Complete study of 93 cases of basic capturing races [IWG] [b]
Re-definition of 5 types of basic capturing races [IWGD] [b] [there was the predecessor Richard Hunter]
Fighting liberties [IGD] [b]
Definition of semeai-eye, stable / unstable eye, strong / weak eye [IGD] [b]
Characterisation of strong semeai-eyes [IWG] [b]
Correction of 6 kinds of mistakes in literature [I] [b]

Joseki

Functional classification of josekis [IG] [b]
Value classification of josekis [IG] [b]
Method of value evaluation of all josekis, except those with global (ko or semeai) fights [ICG] [b]
Application to ca. 400 josekis [IG] [b]
Classification of every move type and meaning occurring in joseki [IGD] [b]
Classification of strategic lines [IG] [b]
Classification of group meanings [IG] [b]
Joseki structure by their strategic choices [WG] [b]

Positional Judgement

Definition of current territory [ICGD] [b] [there was the predecessor Cho Chikun]
Classification of groups [WG] [b]
Classification of regions [IWG] [b]
Positional judgement: various methods, procedures, aspects [IG] [b] or [WG] [b]
Unsettled Group Average [IWGT] [b] [there were predecessors among CGT endgame researchers]
Definition of quiet group, quiet position [IWGD] [b] [there were predecessors among computer-go researchers]

Ko and Other Restrictions

General definition of ko, regardless of position and ruleset [IGD] [p]
General classification and definition of basic-ko types, regardless of position and ruleset [IGD] [p]
Ko and dame endgames under area scoring [IWGT] [pm]
Ko and dame endgames under Ikeda Territory I Rules [IGT] [m]
Cycle Law [IT] [m]
Default Restriction Rules [IG] [p]
Local-ko-intersection [IGD] [p]
Global-ko-intersection [IGD] [p]
Dead Ko [IWGD] [pm]
Closed Death [IGD] [pm]
Semi-stable Ko and its variants [IWGD] [pm]
Definition of external / internal ko [IGD] [p]
Preliminary definitions of pass-fights [IGD] [m]
No frequent pass-fights under Ikeda Territory I Rules [IT] [m]
Preliminary definitions of pass-fights [IGD] [m]

Life + Death and Scoring

Local-1 [WGD] [pm]
Capturable-1, local-2, capturable-2 [IGD] [pm]
Definition of [the scoring term] region [IGD] [pm]
Definition of [the scoring term] territory [IGD] [pm]
Definition of [the scoring term] group [IGD] [m]
Definition of independently-alive [IGD] [pm]
Definition of in-seki, seki [IGD] [pm]
Definition of dame [IGD] [pm]
Definition of eye-point, eye, eye-space [IGD] [pm] [there were predecessors]
Re-definition of two-eye-formation [IGD] [pm]
Alive in Japanese 2003 Rules equals alive in World Amateur Go Championship Rules model [IGT] [bm] [proof Chris Dams, conjecture Robert Jasiek]

Rules

Particular Rules

Fixed-ko-rule [IG] [m]
Natural Situational Superko [IWG] [pm]

Rulesets

Simple Rules [WG] [p]
Multi-player Go Rules [WG] [p]
Japanese 2003 Rules [IG] [p]
Simplified Japanese Rules [IG] [p]
Simplified World Mind Sports Games Rules [IG] [p]

Commentaries

Commentaries on Ing Ko Rules [IG] [p]
Commentaries on Japanese 1989 Rules [IG] [p]
Commentaries on World Amateur Go Championship Rules [IG] [p]
Commentaries on Verbal Japanese Rules [IG] [p]

Theory

Prisoner counting for stone scoring [IT] [m]
Solution for the World Mind Sports Games 2008 Rules' Supplementary Ko Rule [IG] [p]

Shapes

Pendulum Ko [IG] [m]
A new type of double ko [IG] [m]
Infamous Ko [WG] [m]
1 joseki [IG] [b]

Other Terms

Direct connection, indirect connection [IWG] [b]
Mobility / usefulness count / difference [ICG] [b]
Lake, lake size [WG] [b]
Eye value [WG] [b]
Approach block [WG] [b]
External / internal liberty shortage [WG] [b]
Action [IG] [b]
Gote-like, sente-like [IG] [b]
Reduction-or-invasion [IG] [b]
Prisoner-difference [WG] [pm]
Locale [WG] [bm]
Stone difference [IG] [b]
Definition of proto-group [IGD] [b]

Bill Spight's Go Theory Research

Preface
Endgame

Theorems
Other Theory

Ko
Rules

Preface

Bill Spight's teaching of go theory, especially endgame theory, and minor inventions are not listed. He may have done further research I am not aware of. His real name is William L. Spight.

The research is by Bill Spight unless other names are stated. Two or more names without attributes are listed in decreasing order of contribution. Names separated by a slash indicate equal contribution. Besides his ground-breaking structural insight, bold font denotes his most important contribution to the advance of go theory.

Endgame

Theorems

Generalised thermography allowing complex and multiple kos [IGTD] [p] [Bill Spight, Elwyn Berlekamp, Martin Müller et al]
Timing in a neutral threat environment and dependency on Fibonacci numbers [IGT] [p]
Equivalence of conditions (gote / sente count versus gote / follow-up move value versus sente / follow-up move value versus gote / sente move value) of local endgame with one simple follow-up [IGT] [bm] [proofs Robert Jasiek, conjectures Bill Spight]
Non-existence of local double sente [IGT] [bm] [Francisco Criado, Robert Jasiek, Bill Spight]
Equivalence of conditions (gote / sente count versus gote / sente move value) of local endgame with a player's simple gote and sente options [IGT] [bm] [proofs Robert Jasiek, conjectures Bill Spight]
Method of comparing the opponent's branches, 3-move traversal, evaluation due to reversal [IGT] [bm] [Bill Spight, Robert Jasiek]
Timing during the late endgame at low temperature of the creator playing in a local endgame with one follow-up in an environment [IGT] [bm] [Bill Spight, Robert Jasiek]
Method of comparing two sequences combined with the method of comparing counts during the late endgame in a local endgame with one follow-up in an environment [IGT] [bm] [Robert Jasiek, Bill Spight]
Method of comparing two sequences combined with the method of comparing net profits during the late endgame in a local endgame with one follow-up in an environment [IGT] [bm] [Robert Jasiek, Bill Spight]
Method of comparing three sequences combined with the method of comparing counts during the late endgame of the creator playing in a local endgame with gote and sente options in an environment [IGT] [bm] [Robert Jasiek, Bill Spight]
Timing during the late endgame at low temperature of the creator playing in a local endgame with gote and sente options in an environment [IGT] [bm] [Bill Spight, Robert Jasiek]
Timing during the early endgame at low temperature of the creator playing in a local endgame with gote and sente options in an environment [IGT] [bm]
Creator starting in the larger local endgame with one follow-up [IGT] [bm] [Robert Jasiek, Bill Spight]
Preventer starting in the larger local endgame with one follow-up [IGT] [bm] [Robert Jasiek, Bill Spight]
Additional details for playing in the larger local endgame with one follow-up [IGT] [bm] [Bill Spight, Robert Jasiek]

Other Theory

Neutral threat environment [ICGD] [pm] [Elwyn Berlekamp / Bill Spight]
Continued research in temperature theory [G] [pm]
'Ambiguous' local endgame (hybrid of local gote and sente) [ICGD] [m]
Local endgames with gote and sente options require their own evaluation. [G] [m]
Preliminary theory of evaluating sequences [G] [m]
Comparison of gote versus sente strategies in multiples [C] [m]
Clarification of gain [CGW] [m]
Translation of theory on unconnected reductions of corridors [IGT] [pm] [theorem + proof: David Wolfe, translation: Bill Spight]
First examples of a few rare cases [I] [m]
Doubly ambiguous shapes [W] [m] [Bill Spight / Robert Jasiek]
Verify types of local endgames to determine their correct values. [IGT] [bm] [Robert Jasiek / Bill Spight]
Fast evaluation of long sequences by the method of comparing the opponent's branches [IG] [b] [Bill Spight, Robert Jasiek et al]
Do not always play in decreasing order of move values but use better theory. [IGT] [bm] [Robert Jasiek, Bill Spight]
Interrupt local sequences in time. [IGT] [bm] [Robert Jasiek / Bill Spight]
Strategy depends on the local endgame / ensemble, the environment, its temperature and sometimes its second-largest value. [IGT] [bm] [Robert Jasiek / Bill Spight]
Use of the sente move value for the timing during the late endgame of playing in a local gote. [IGT] [bm]
Application to strategy and positional judgement during the middle game [IGT] [bm] [Bill Spight, Robert Jasiek]
Earliest and latest moments of playing in a local endgame in sente or reverse sente depending on the enironment [IGT] [bm] [Bill Spight, Robert Jasiek]
Translation of relevant combinatorial game theory (including low-level theory and corridors) to go theory. [IGT] [bm] [Robert Jasiek, Bill Spight et al]
Types (local gote, local sente, ambiguous of a local endgame with one simple follow-up. [ID] [m]
Test sequences for a local endgame with one follow-up in an environment [ID] [bm] [Bill Spight, Robert Jasiek]
Test sequences for the creator starting in a local endgame with gote and sente options in an environment [ID] [bm] [Bill Spight, Robert Jasiek]

Ko

Correct play in multiple n-tuple kos [IGT] [m] [Bill Spight / James Davies / John Rickard]
Komonster [ICGD] [m]
Primary, secondary, tertiary ko threats [ICG] [m]

Rules

Spight Rules [I] [m]
Pass stones (aka book-keeping stones) [ICG] [p]
Research in button go [C] [m]
A type of superko rules [I] [m]