As in Stockfish: https://www.quora.com/What-is-the-algorithm-behind-Stockfish-the-chess-engine

https://www.computer-museum.ru/english/m20.htm

` 1956 – Los Alamos chess is the first program to play a chess-like game, developed by Paul Stein and Mark Wells for the MANIAC I computer.`

!! **1956 – John McCarthy invents the alpha-beta search algorithm.**

1957 – The first programs that can play a full game of chess are developed, one by Alex Bernstein[39] and one by Russian programmers using a BESM.

1958 – NSS becomes the first chess program to use the alpha-beta search algorithm.

1962 – The first program to play credibly, Kotok-McCarthy, is published at MIT.

1963 – Grandmaster David Bronstein defeats an **M-20** running an early chess program.[40]

1966–67 – The first chess match between computer programs is played. Moscow Institute for Theoretical and Experimental Physics (ITEP) defeats Kotok-McCarthy at Stanford University by telegraph over nine months.

1967 – Mac Hack VI, by Richard Greenblatt et al. introduces transposition tables and employs dozens of carefully tuned move selection heuristics; it becomes the first program to defeat a person in tournament play. Mac Hack VI played about C class level.

1968 – Scottish chess champion David Levy makes a 500 pound bet with AI pioneers John McCarthy and Donald Michie that no computer program would win a chess match against him within 10 years.

1970 – Monty Newborn and the Association for Computing Machinery organize the first North American Computer Chess Championships in New York.

1971 – Ken Thompson, an American Computer scientist at Bell Labs and creator of the Unix operating system, writes his first chess-playing program called "chess" for the earliest version of Unix.[41]

1974 – David Levy, Ben Mittman and Monty Newborn organize the first World Computer Chess Championship which is won by the Russian program Kaissa.

1975 – After nearly a decade of only marginal progress since the high-water mark of Greenblatt's MacHack VI in 1967, Northwestern University Chess 4.5 is introduced featuring full-width search, and innovations of bitboards and iterative deepening. It also reinstated a transposition table as first seen in Greenblatt's program. **It was thus the first program with an integrated modern structure and became the model for all future development.** Chess 4.5 played strong B-class *{USCF 1600-1799}* and won the 3rd World Computer Chess Championship that year. Northwestern University Chess and its descendants dominated computer chess until the era of hardware chess machines in the early 80's.

1976 – In December, Canadian programmer Peter R. Jennings releases Microchess, the first game for microcomputers to be sold.[42]

Released in 1977, Boris was one of the first chess computers to be widely marketed. It ran on a Fairchild F8 8-bit microprocessor with only 2.5 KiB ROM and 256 byte RAM.

1977 – In March, Fidelity Electronics releases Chess Challenger, the first dedicated chess computer to be sold. The International Computer Chess Association is founded by chess programmers to organize computer chess championships and report on research and advancements on computer chess in their journal. Also that year, Applied Concepts released Boris, a dedicated chess computer in a wooden box with plastic chess pieces and a folding board.

1978 – David Levy wins the bet made 10 years earlier, defeating Chess 4.7 in a six-game match by a score of 4½–1½. The computer's victory in game four is the first defeat of a human master in a tournament.[9]

. . .

https://www.computer-museum.ru/english/m20.htm

**М-20** - an Electronic Computing Machine for General Computations.

Chief designer was academician of the AS USSR S. A. Lebedev; chief developer assistants were M.K. Soulim (PhD in engineering) and M.R. Shura-Bura (PhD in physics and math); the development team: P.P. Golovistikov (PhD in engineering), V.Ya. Alekseyev (PhD in engineering), V.V. Bardizh (PhD in engineering), V.N. Laut (PhD in engineering), A.A. Sokolov, M.V. Tyapkin, A.S. Fyodorov.

Developing organization: the Institute of Precise Mechanics and Computation Equipment (ITM and VT) and the Special design bureau No. 245 (SKB-245).

Producer: Kazan Plant of Computing Machines.

Development stage was completed by 1958.

Manufacturing started in 1958.

Manufacturing stopped in 1964.

Number of computers produced - **20**.

Applications: solving tasks in various fields of science and engineering.

M-20 was a single-processor computer. Several original architectural solutions were implemented in the processor: overlapping the executed commands (i.e. pipeline processing), accelerated addition and multiplying operations (due to improved operating of carry circuits - the "rough" carry chain was introduced in addition to fly-through carry) and multiplying a factor by two bits at a time. The computer used **45-bit binary floating point** notation. Its main memory was based on ferromagnetic cores and held up to **4096 words**. The peripheral memory consisted of magnetic drums and tapes.

Circuitry: **dismountable blocks of two electronic tubes**. The impulse principle (dynamic triggers) was applied in the circuits of parallel devices; thereby the total amount of computer valves was reduced to **1600 items**. The logical circuits used semiconductor diodes that were exploited unexcessively due to the dynamic triggering method. This allowed to make the computer operation more reliable.

Architecture and technology: the computer occupied seven boxes. Each box contained six cards (circuit boards). 30-pin knife-edge plugs were used.

System software: the IS-2 library of standard subroutines.

Characteristics:

Average performance - **20 thousand instructions per second**.

Occupied area - **170-200 sq. m**.

Consumed power - **50 kW **(not including the cooling system); the standard 220V/50Hz power circuit was used for M-20.

Main features: **The M-20 computer was one of the fastest and most reliable of the first-generation computers all over the world. **The general improvement of overall performance was achieved due to new architectural solutions and impulse principle of the circuit structure as well as to introducing:

index arithmetic that in many cases allowed to avoid command variables;

new logical operations of the processor;

instruction sets with automatic address changing;

overlapping arithmetic unit operation and fetching commands from the main memory;

overlapping data output and operation of the processor.

The M-20 computer and some of its components were patented. There were numerous publications on the subject.

One key omission: "Programming a computer for playing chess." Claude Shannon, 1949. The origin of the minimax search procedure. Claude was a pioneer. Minimax. Later built a relay-based machine to play K+R vs K, which while a simple ending, in the early 50's it was very complex with a lack of computer time / speed.

I got to meet him a couple of times. Somewhere in the 90's, he was following Crafty since it had public source, and he would call to ask questions or discuss ideas. At some point (before his death somewhere around 2000) he sent me a signed copy of his original paper cited above, and an autographed/framed picture of his KR vs K chess machine with him and one of the Laskers included.

Golden age of computer chess as it all started.

I got to meet him a couple of times. Somewhere in the 90's, he was following Crafty since it had public source, and he would call to ask questions or discuss ideas. At some point (before his death somewhere around 2000) he sent me a signed copy of his original paper cited above, and an autographed/framed picture of his KR vs K chess machine with him and one of the Laskers included.

Golden age of computer chess as it all started.

Thanks for the information!

Shannon's very impressive accomplishments, many far beyond chess, are mentioned https://en.wikipedia.org/wiki/Claude_Shannon .

For example: "

Although the Wikipedia artice above does not mention it {maybe they could be contacted for inclusion?} this, and the photo below, is from https://www.chess.com/article/view/the-man-who-built-the-chess-machine :

"

---

An even simpler machine was made 37 years earlier, from https://en.wikipedia.org/wiki/El_Ajedrecista :

"

https://books.google.com/books?id=xLVdDgAAQBAJ&lpg=PA31&dq=Torres+and+his+remarkable+automatic+devices.+Issue+2079+of+Scientific+American,+1915&pg=PA30&redir_esc=y#v=onepage&q&f=false

---

[Event "move/10 minutes"]

[Site "Tablebase draw"]

[Date "May 18, 2020"]

[Round "?"]

[White "Stockfish_20050217"]

[Black "No Syzygy, R7 2700K"]

[Result ""]

[BlackElo "2400"]

[Time "14:33:22"]

[WhiteElo "2000"]

[TimeControl "0+600"]

[SetUp "1"]

[FEN "8/6k1/8/1r6/R4PKP/8/8/8 w - - 0 1"]

[Termination "unterminated"]

[PlyCount "1"]

[WhiteType "program"]

[BlackType "human"]

1. f5 {+2.11/81 600 seconds, 60,703,000 nodes/second, 36.4 billion nodes}

({PV} 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2

14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Ke5 Rb5+ 18.Kf6 Rb6+ 19.Kg5 Rb2 20.Rh3 Rg2+ 21.Kf6 Rb2 22.Kf7 Rb7+ 23.Ke6 Rb6+ 24.Kd5 Rb5+

25.Ke4 Rb4+ 26.Ke5 Rb5+ 27.Kf4 Rb6 28.Kg5 Rb2 29.Rf3 Rg2+ 30.Kf6 Ra2 31.Rb3 Ra1 32.Rc3 Rf1 33.Ra3 Rb1 34.Ra8 Rf1 35.Rb8 Rg1 36.Rb6 Rf1

37.Re6 Rf2 38.Re3 Ra2 39.Re4 Rb2 40.Re1 Rb3 41.Re2 Rb1 42.Rh2 Rc1 43.Kg5 Rg1+ 44.Kf4 Ra1 45.Rh3 Ra6 46.Kg5 Ra2 47.Rh5 Ra6)

(1.Ra7+ {0.00 Syzygy 6, ply 1})

*

Shannon's very impressive accomplishments, many far beyond chess, are mentioned https://en.wikipedia.org/wiki/Claude_Shannon .

For example: "

`... His process for having the computer decide on which move to make was a minimax procedure, based on an evaluation function of a given chess position. Shannon gave a rough example of an evaluation function in which the value of the black position was subtracted from that of the white position. Material was counted according to the usual chess piece relative value (1 point for a pawn, 3 points for a knight or bishop, 5 points for a rook, and 9 points for a queen).[43] He considered some positional factors, subtracting ½ point for each doubled pawn, backward pawn, and isolated pawn; mobility was incorporated by adding 0.1 point for each legal move available. ..."`

.Although the Wikipedia artice above does not mention it {maybe they could be contacted for inclusion?} this, and the photo below, is from https://www.chess.com/article/view/the-man-who-built-the-chess-machine :

"

`... Completed in 1949, the machine was referred to as both Endgame and Caissac (after the fictional “patron goddess of chess,” Caïssa). As the name suggested, Shannon’s machine could only handle endgames, managing no more than six pieces at a time.`

More than 150 relay switches were used to calculate a move, processing power that allowed the machine to decide within a respectable 10 to 15 seconds. The relays were concealed in a box decorated with the pattern of a chess board; once they had chosen a move, a series of lights would indicate it to the user.

Simple as it was, it was one of the world’s very first chess-playing computers, ...

".---

An even simpler machine was made 37 years earlier, from https://en.wikipedia.org/wiki/El_Ajedrecista :

"

`El Ajedrecista (English: The Chess Player) is an automaton built in 1912 by Leonardo Torres y Quevedo, one of the first autonomous machines capable of playing chess.[2] As opposed to the human-operated The Turk and Ajeeb, El Ajedrecista was a true automaton built to play chess without human guidance. It played an endgame with three chess pieces, automatically moving a white king and a rook to checkmate the black king moved by a human opponent.`

The device could be considered the first computer game in history.[3] It created great excitement when it made its debut, at the University of Paris in 1914. It was first widely mentioned in Scientific American as "Torres and His Remarkable Automatic Devices" on November 6, 1915.[4]

The automaton does not deliver checkmate in the minimum number of moves, nor always within the 50 moves allotted by the fifty-move rule, because of the simple algorithm that calculates the moves. It did, however, checkmate the opponent every time. If an illegal move was made by the opposite player, the automaton would signal it.[5] ...

". Also below from page 31 of the preview at:https://books.google.com/books?id=xLVdDgAAQBAJ&lpg=PA31&dq=Torres+and+his+remarkable+automatic+devices.+Issue+2079+of+Scientific+American,+1915&pg=PA30&redir_esc=y#v=onepage&q&f=false

---

[Event "move/10 minutes"]

[Site "Tablebase draw"]

[Date "May 18, 2020"]

[Round "?"]

[White "Stockfish_20050217"]

[Black "No Syzygy, R7 2700K"]

[Result ""]

[BlackElo "2400"]

[Time "14:33:22"]

[WhiteElo "2000"]

[TimeControl "0+600"]

[SetUp "1"]

[FEN "8/6k1/8/1r6/R4PKP/8/8/8 w - - 0 1"]

[Termination "unterminated"]

[PlyCount "1"]

[WhiteType "program"]

[BlackType "human"]

1. f5 {+2.11/81 600 seconds, 60,703,000 nodes/second, 36.4 billion nodes}

({PV} 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2

14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Ke5 Rb5+ 18.Kf6 Rb6+ 19.Kg5 Rb2 20.Rh3 Rg2+ 21.Kf6 Rb2 22.Kf7 Rb7+ 23.Ke6 Rb6+ 24.Kd5 Rb5+

25.Ke4 Rb4+ 26.Ke5 Rb5+ 27.Kf4 Rb6 28.Kg5 Rb2 29.Rf3 Rg2+ 30.Kf6 Ra2 31.Rb3 Ra1 32.Rc3 Rf1 33.Ra3 Rb1 34.Ra8 Rf1 35.Rb8 Rg1 36.Rb6 Rf1

37.Re6 Rf2 38.Re3 Ra2 39.Re4 Rb2 40.Re1 Rb3 41.Re2 Rb1 42.Rh2 Rc1 43.Kg5 Rg1+ 44.Kf4 Ra1 45.Rh3 Ra6 46.Kg5 Ra2 47.Rh5 Ra6)

(1.Ra7+ {0.00 Syzygy 6, ply 1})

*

FEN: 8/6k1/8/1r6/R4PKP/8/8/8 w - - 0 1 Stockfish_20050217: 1/2 00:00 442 442k +2.02 1.Ra7+ Kf6 ... 14/27 00:00 617k 26,830k +2.69 1.f5 Rb1 2.Kg5 Rg1+ 3.Rg4 Ra1 4.Rg2 Re1 5.h5 Rb1 6.h6+ Kh7 7.Rg4 Rb2 8.Rg3 Rb1 9.Rg2 Re1 10.f6 Re5+ 11.Kf4 Re8 ... 46/55 00:01 51,579k 36,607k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh3 Ra1 14.Rb3 Ra2 15.Re3 Rb2 16.Rh3 Rb1 17.Rh2 Rb5 18.Kg5 Rb1 19.Re2 Rg1+ 20.Kf6 Ra1 21.Re8 Ra2 22.Rc8 Ra1 23.Rb8 Ra2 24.Re8 Ra1 25.Rc8 Rb1 26.Ra8 Rb2 27.Rd8 Ra2 28.Rd1 47/62 00:02 66,313k 37,255k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh3 Ra1 14.Rb3 Ra2 15.Re3 Rb2 16.Rh3 Rb1 17.Rh2 Rb5 18.Kg5 Rb1 19.Re2 Rg1+ 20.Kf6 Rb1 21.Re4 Rb3 22.Rh4 Rb6+ 23.Kg5 Rb1 24.Ra4 Rg1+ 25.Kf6 Rg2 26.Ra8 Rg1 27.Rb8 Ra1 28.Re8 Ra2 29.Re6 Kxh6 30.Ke7+ Kh7 31.f6 Ra8 ... 71/84 00:42 2,150,654k 50,972k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2 14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Kd7 Rb7+ 18.Kd6 Rb6+ 19.Kc7 Rf6 20.Rh5 Ra6 21.Kd7 Ra7+ 22.Kd6 Ra6+ 23.Ke5 Ra4 24.Rh1 Ra5+ 25.Kf6 Ra6+ 26.Kg5 Ra2 27.Kf4 Ra6 28.Rh2 Ra1 29.Rh3 Ra6 30.Kg5 Ra1 31.Rb3 Rg1+ 32.Kf6 Ra1 33.Rb8 Rg1 34.Ra8 Rg2 35.Rd8 Rb2 36.Rd3 Rf2 37.Ra3 Rg2 38.Ra8 Rf2 39.Rb8 Rg2 40.Kf7 Ra2 41.Re8 Kxh6 72/87 00:43 2,202,292k 51,038k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2 14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Kd7 Rb7+ 18.Kd6 Rb6+ 19.Kc7 Rf6 20.Rh5 Ra6 21.Kd7 Ra7+ 22.Kd6 Ra8 23.Ke6 Ra6+ 24.Kd5 Rb6 25.Rh3 Rb5+ 26.Ke6 Rb6+ 27.Ke5 Ra6 28.Rh4 Rb6 29.Rh2 Ra6 30.Kf4 Ra1 31.Rh3 Ra6 32.Kg5 Ra2 33.Rc3 Rg2+ 34.Kf6 Rb2 35.Ra3 Rf2 36.Rh3 Rg2 37.Kf7 Ra2 38.Rh4 Ra7+ 39.Kf6 Ra6+ 40.Kg5 Ra2 41.Re4 Rg2+ 42.Kf6 Rf2 43.Re8 Ra2 44.Re3 73/88 04:11 14,903,923k 59,228k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2 14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Kd7 Rb7+ 18.Kd6 Rb6+ 19.Kc7 Rf6 20.Rh5 Ra6 21.Kd7 Ra7+ 22.Kd6 Ra8 23.Ke6 Ra6+ 24.Kd5 Rb6 25.Rh3 Rb5+ 26.Ke6 Rb6+ 27.Ke5 Ra6 28.Rh4 Rb6 29.Rh2 Rb5+ 30.Ke6 Rb6+ 31.Ke7 Rb7+ 32.Kd6 Rb6+ 33.Kc5 Rf6 34.Rh5 Ra6 35.Kd4 Ra4+ 36.Ke5 Ra5+ 37.Kf6 Ra6+ 38.Kg5 Ra1 39.Rh3 Rg1+ 40.Kf6 Rg2 41.Kf7 Ra2 42.Rh1 Ra7+ 43.Kf6 Ra6+ 44.Kg5 Ra2 74/90 04:13 14,973,476k 59,219k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2 14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Ke5 Rb5+ 18.Kf6 Rb6+ 19.Kg5 Rb2 20.Rg4 Rb1 21.Rd4 Rg1+ 22.Kf6 Rb1 23.Rd8 Rb3 24.Kg5 Rg3+ 25.Kf4 Rh3 26.Rd6 Rh1 27.Ra6 Rf1+ 28.Ke5 Re1+ 29.Kf6 Rf1 30.Ra8 Rh1 31.Ra7+ Kxh6 32.Ra4 Rh3 33.Ra1 Rh2 34.Rd1 Rh3 35.Rb1 Rh2 36.Rb3 Rh4 37.Rc3 Rh2 38.Rf3 Rh4 39.Rb3 Rh1 40.Rg3 Rh2 41.Rc3 Rh1 42.Rc4 Rh3 43.Rc8 Kh7 44.Kf7 75/93 04:14 15,028,247k 59,212k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2 14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Ke5 Rb5+ 18.Kf6 Rb6+ 19.Kg5 Rb2 20.Rg4 Rb1 21.Rd4 Rg1+ 22.Kf6 Rb1 23.Rd8 Rb3 24.Kg5 Rg3+ 25.Kf4 Rh3 26.Rd6 Rh1 27.Ra6 Rf1+ 28.Ke5 Re1+ 29.Kf6 Rf1 30.Ra8 Rb1 31.Rc8 Rf1 32.Rb8 Rg1 33.Rb6 Rf1 34.Rb2 Rh1 35.Rb7+ Kxh6 36.Rb3 Rh4 37.Rf3 Rh1 38.Re3 Rh4 39.Rb3 Rh1 40.Rf3 Rh4 41.Rf1 Rh3 42.Rg1 Rh4 43.Rd1 Rh3 44.Ke6 Ra3 45.Rh1+ Kg5 46.Rg1+ Kh6 76/93 04:15 15,108,102k 59,206k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2 14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Ke5 Rb5+ 18.Kf6 Rb6+ 19.Kg5 Rb2 20.Rg4 Rb1 21.Rd4 Rg1+ 22.Kf6 Rb1 23.Rd8 Rb3 24.Kg5 Rg3+ 25.Kf4 Rh3 26.Rd6 Rh1 27.Ra6 Rf1+ 28.Ke5 Re1+ 29.Kf6 Rf1 30.Ra8 Rb1 31.Rc8 Rf1 32.Rb8 Rg1 33.Rb6 Rf1 34.Rb2 Rh1 35.Rb7+ Kxh6 36.Rb3 Rh4 37.Rd3 Rh2 38.Rg3 Rh1 39.Rc3 Rh2 40.Rd3 Rh4 41.Rd1 Rh3 42.Re1 Rh2 43.Re8 Kh7 44.Ke6 Rb2 45.f6 77/92 04:16 15,178,586k 59,205k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2 14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Ke5 Rb5+ 18.Kf6 Rb6+ 19.Kg5 Rb2 20.Rg4 Rb1 21.Rd4 Rg1+ 22.Kf6 Rb1 23.Rd8 Rb3 24.Kg5 Rg3+ 25.Kf4 Rh3 26.Rd6 Rh1 27.Ra6 Rf1+ 28.Ke5 Re1+ 29.Kf6 Rf1 30.Ra8 Rb1 31.Rc8 Rf1 32.Rb8 Rg1 33.Rb6 Rf1 34.Rb2 Rh1 35.Re2 Kxh6 36.Re4 Rh3 37.Rc4 Rh1 38.Rc3 Rh2 39.Re3 Rh1 40.Re2 Rh3 41.Rb2 Rh4 42.Rg2 Rh3 43.Rg8 Kh7 44.Rg7+ Kh8 45.Re7 Kg8 46.Re8+ Kh7 78/96 04:20 15,426,531k 59,212k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2 14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Ke5 Rb5+ 18.Kf6 Rb6+ 19.Kg5 Rb2 20.Rg4 Rb1 21.Rd4 Rg1+ 22.Kf6 Rb1 23.Rd8 Rb3 24.Kg5 Rg3+ 25.Kf4 Rh3 26.Rd6 Rh1 27.Ra6 Rf1+ 28.Ke5 Re1+ 29.Kf6 Rf1 30.Ra8 Rb1 31.Rc8 Rf1 32.Rb8 Rg1 33.Rb6 Rf1 34.Rb2 Rh1 35.Rf2 Rb1 36.Rh2 Rb6+ 37.Kg5 Rb1 38.Rh3 Rg1+ 39.Kf6 Rb1 40.Rc3 Ra1 41.Re3 Ra2 42.Re6 Kxh6 43.Ke7+ Kh7 44.f6 Ra8 45.Kf7 Rb8 46.Re7 Ra8 47.Re4 Ra7+ 48.Ke6 Kg6 49.Rg4+ Kh7 79/101 04:24 15,631,461k 59,245k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2 14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Ke5 Rb5+ 18.Kf6 Rb6+ 19.Kg5 Rb2 20.Rh3 Rg2+ 21.Kf6 Rb2 22.Kf7 Rb7+ 23.Ke6 Rb6+ 24.Kd5 Rb5+ 25.Ke4 Rb4+ 26.Ke5 Rb5+ 27.Kf4 Rb6 28.Kg5 Rb2 29.Rf3 Rg2+ 30.Kf6 Ra2 31.Rb3 Ra1 32.Rc3 Rf1 33.Ra3 Rg1 34.Ra8 Rg3 35.Rd8 Rb3 36.Kg5 Rg3+ 37.Kf4 Rh3 38.Rd6 Rh1 39.Ra6 Rf1+ 40.Ke5 Re1+ 41.Kf6 Rf1 42.Ra8 Rb1 43.Rc8 Rf1 44.Re8 Ra1 45.Re2 Rb1 46.Rh2 Rc1 47.Ke5 Rc5+ 48.Ke6 Rc6+ 49.Kd5 Rb6 50.Ke4 Rb4+ 51.Ke5 80/98 04:27 15,845,504k 59,270k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2 14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Ke5 Rb5+ 18.Kf6 Rb6+ 19.Kg5 Rb2 20.Rh3 Rg2+ 21.Kf6 Rb2 22.Kf7 Rb7+ 23.Ke6 Rb6+ 24.Kd5 Rb5+ 25.Ke4 Rb4+ 26.Ke5 Rb5+ 27.Kf4 Rb6 28.Kg5 Rb2 29.Rf3 Rg2+ 30.Kf6 Ra2 31.Rb3 Ra1 32.Rc3 Rf1 33.Ra3 Rb1 34.Ra8 Rf1 35.Rb8 Rg1 36.Rb6 Rf1 37.Re6 Rf2 38.Re3 Ra2 39.Re4 Rb2 40.Re1 Rb3 41.Re2 Rb1 42.Rh2 Rc1 43.Kg5 Rg1+ 44.Kf4 Ra1 45.Rh3 Ra6 46.Kg5 Ra2 47.Rh5 Ra6 81/98 10:00 36,421,912k 60,703k +2.11 1.f5 Rb2 2.Kg5 Rg2+ 3.Rg4 Ra2 4.h5 Rb2 5.h6+ Kh7 6.Rg1 Ra2 7.Rd1 Rg2+ 8.Kf6 Ra2 9.Re1 Rb2 10.Re4 Rb1 11.Re2 Rb3 12.Rh2 Rb1 13.Rh5 Rb2 14.Kf7 Rb6 15.Rh4 Rb7+ 16.Ke6 Rb6+ 17.Ke5 Rb5+ 18.Kf6 Rb6+ 19.Kg5 Rb2 20.Rh3 Rg2+ 21.Kf6 Rb2 22.Kf7 Rb7+ 23.Ke6 Rb6+ 24.Kd5 Rb5+ 25.Ke4 Rb4+ 26.Ke5 Rb5+ 27.Kf4 Rb6 28.Kg5 Rb2 29.Rf3 Rg2+ 30.Kf6 Ra2 31.Rb3 Ra1 32.Rc3 Rf1 33.Ra3 Rb1 34.Ra8 Rf1 35.Rb8 Rg1 36.Rb6 Rf1 37.Re6 Rf2 38.Re3 Ra2 39.Re4 Rb2 40.Re1 Rb3 41.Re2 Rb1 42.Rh2 Rc1 43.Kg5 Rg1+ 44.Kf4 Ra1 45.Rh3 Ra6 46.Kg5 Ra2 47.Rh5 Ra6

Why do alpha beta searches go random (kamikaze) when the position is totally lost though not yet forced mate in the horizon? Why not still pick the slowest way to lose?

It doesn't do it if it's -2, but -5, say, it goes into complete suicide mode. Why this arbitrary cut-off for randomness at a certain eval?

It doesn't do it if it's -2, but -5, say, it goes into complete suicide mode. Why this arbitrary cut-off for randomness at a certain eval?

What you are seeing is an artifact called "the horizon effect." I used to have a good position to illustrate this but it has been lost. The idea is this. (and it doesn't have to be in a losing position either). Suppose the computer takes your rook with its rook, leaving the rook in a trapped position. Since you can take it at any time, the program can conclude "I am going to lose that rook, but if I throw away this knight, I can't see the rook being taken, so here goes the knight. The next move the same thing occurs. It keeps pushing off the loss of the rook until it loses the game. Usually when the program throws things away, it is trying to delay an even greater loss that it can't avoid. Looks stupid. Is stupid. Fortunately with today's programs, they see deeply enough that this is not very common.

Okey. Why does it expect me to take a piece which is worth less in the following move rather than just grab the rook right away?

I am surprised that Shannon's seminal work was not considered given its importance in computer science and engineering.

Unfortunately unlike today's academic requirements, Shannon did not have the level of citations used today.

I recall a text book from the early 1930s called

Unfortunately unlike today's academic requirements, Shannon did not have the level of citations used today.

I recall a text book from the early 1930s called

*Computer Chess*.
Shannons approach has not fared well in practise. For what it's worth, Deep Junior utilized the Shannon search heuristic.

Monte Carlo has been innaccurately likened to Shannon search B type, when it's nothing of the sort.

Monte Carlo has been innaccurately likened to Shannon search B type, when it's nothing of the sort.

I don't think type A or type B have fared poorly. We are just seeing a unification. IE the basic search of today is type-A. Full width. But then with null-move, and LMR/LMP and such, we are seeing type-B concepts combined. And while Shannon didn't explicitly mention (say) null-move. Using null-move fits cleanly within his definitions.

Type B is by definition only looking at important branches.

Here's what computer wiki says

Inspired by the experiments of Adriaan de Groot [3] , Shannon and early programmers favored Type B strategy. Type B searches use some type of static heuristics in order to only look at branches that look important - with some risk to oversee some serious tactics not covered by the plausible move selector. Type B was most popular until the 1970's, when Type A programs had enough processing power and more efficient brute force algorithms to become stronger. Today most programs are closer to Type A, but have some characteristics of a Type B as mentioned in selectivity.

Here's what computer wiki says

Inspired by the experiments of Adriaan de Groot [3] , Shannon and early programmers favored Type B strategy. Type B searches use some type of static heuristics in order to only look at branches that look important - with some risk to oversee some serious tactics not covered by the plausible move selector. Type B was most popular until the 1970's, when Type A programs had enough processing power and more efficient brute force algorithms to become stronger. Today most programs are closer to Type A, but have some characteristics of a Type B as mentioned in selectivity.

Speaking of extreme early computer chess, I found this from 1977:

- The hardware needed for USCF 1935 rating, Chess 4.6 (similar to the Chess 4.5 mentioned above).

- The first microprocessor (Intel 8080) based program to play in a computer tournament.

https://www.lkessler.com/brutefor.shtml

CDC Cyber 170 series computer room - 1987:

- The hardware needed for USCF 1935 rating, Chess 4.6 (similar to the Chess 4.5 mentioned above).

- The first microprocessor (Intel 8080) based program to play in a computer tournament.

https://www.lkessler.com/brutefor.shtml

`Seattle, Washington, 1977 - The 8th N.A.C.C.C`

The Association of Computing Machinery was about to sponsor its 8th Annual Computer Chess Tournament. Twelve programs were to compete at the Olympic Hotel in Seattle on October 15-17. These included eight American and four Canadian programs. Nine were mainframe programs, two ran on minicomputers, and *there was one "microcomputer". 8080 Chess was to be the first microcomputer to participate in a computer chess tournament.* **CHESS 4.6** was the reigning champion, had the highest **USCF rating of 1935**, was running on the most powerful computer, and was the odds-on favorite to win again. The participants included:

BLACK KNIGHT Fred Prouse et al. Sperry Univac UNIVAC 1110, Roseville, Minn.

BLITZ V Robert Hyatt U. of Southern Mississippi Xerox Sigma 9, Hattiesburg (USM)

BRUTE FORCE Louis Kessler U. of Manitoba IBM 370/168, Winnipeg, Manitoba

CHAOS Fred Swartz et al. U. of Michigan Amdahl 470 V/6, Sunnyvale, California

**CHESS 4.6** David Slate & Larry Atkin Northwestern University **CDC Cyber 176**, Arden Hills, Minn.

CHUTE 1.2 Mike Valenti U. of Toronto Amdahl 470 V/6, Montreal, Quebec

DUCHESS Tom Truscott Duke University IBM 370/165, North Carolina

OSTRICH Monroe Newborn McGill University Nova 3, Montreal, Quebec

TYRO Albert Zobrist & Fredric Carlson Jet Propulsion Lab. PDP-10 KL, U. of Southern CA

WITA Tony Marsland U. of Alberta Amdahl 470 V/6, Edmonton, Alberta

XENARBOR Donald Miller Control Data Services IBM 370/158, Cleveland, Ohio

*8080 CHESS* Robert Arnstein Processor Technology, Inc. *At Site {microprocessor}*

Six large upright chess-display boards with magnetic-based chess pieces were set up on the stage. A volunteer manned each board and moved the pieces as the game progressed. David Levy, an International Master and the tournament director would walk up and down the stage and provide commentary and analysis for the benefit of the audience as the games progressed.

Directly in front of the platform on the floor were six long double-tables cluttered, variously, with papers, chess boards, and DECwriter terminal/printers connected via long distance to the participants' computers that were in many cases several thousand miles away - except for the one microcomputer that was on site.

CDC Cyber 170 series computer room - 1987:

Most engine authors back in the day don't seem to have programmed a queen value of 9...

Whenever there's queen vs two rooks in an equal game, the oldie engines tend to think it's close to 0.00, which means they probably have the queen at 10.

Alexander Grischuk has the queen at 10 and rooks at 5 each.

Whenever there's queen vs two rooks in an equal game, the oldie engines tend to think it's close to 0.00, which means they probably have the queen at 10.

Alexander Grischuk has the queen at 10 and rooks at 5 each.

https://en.wikipedia.org/wiki/Jean-Baptiste_Alphonse_Karr

"

"

**In 1839** Alphonse Karr became editor of Le Figaro, to which he had been a constant contributor; and he also started a monthly journal, Les Guêpes, of a keenly satirical tone, a publication which brought him the reputation of a somewhat bitter wit. His epigrams are frequently quoted, for example "plus ça change, plus c'est la même chose"[1]—"*the more things change, the more they continue to be the same thing*[2], usually translated as "the more things change, the more they stay the same," (Les Guêpes, July 1848)[3]. ...

"
Back in the late 1980's, I thought the queen was 10 and rooks were both 5. So I said so on a chess programming board. Immediately I was told by several programmers that two rooks were worth more than a queen.

Some of them, like Bobs Crafty, values two rooks higher. I definitely think two rooks are better than a queen as a general principle.

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