Update

chess.md

@@ -19,7 +19,7 @@ Chess as a game is not and cannot be copyrighted, but **can chess games (moves p
 
 ## Chess In General
 
-Chess evolved from ancient board games in India in about 6th century. Nowadays the game is internationally governed by **FIDE** which has taken the on role of an authority that defines the official rules: FIDE rules are considered to be the standard chess rules. FIDE also organizes tournaments, promotes the game and keeps a list of registered players whose performance it rates with so called Elo system –⁠ based on the performance it also grants titles such as **Grandmaster** (GM, strongest), **Internation Master** (IM, second strongest) or **Candidate Master** (CM).
+Chess evolved from ancient board games in India in about 6th century. Nowadays the game is internationally governed by **FIDE** which has taken the on role of an authority that defines the official rules: FIDE rules are considered to be the standard chess rules. FIDE also organizes tournaments, promotes the game and keeps a list of registered players whose performance it rates with so called Elo system –⁠ based on the performance it also grants titles such as **Grandmaster** (GM, strongest), **Internation Master** (IM, second strongest) or **Candidate Master** (CM). A game of chess is so interesting in itself that chess is usually not played for money like many other games ([poker](poker.md), [backgammon](backgammon.md), ...).
 
 A single game of chess is seen as consisting of three stages: **opening** (starting, theoretical "book" moves, developing pieces), **middlegame** (seen as the pure core of the game) and **endgame** (ending in which only relatively few pieces remain on the board). There is no clear border between these stages and they are sometimes defined differently, however each stage plays a bit differently and may require different skills and strategies; for example in the endgame king becomes an active piece while in the opening and middlegame he tries to stay hidden and safe.
 
@@ -61,10 +61,12 @@ Playing strength is not the only possible measure of chess engine quality, of co
 
 { Nanochess is actually pretty strong, in my testing it easily beat [smallchesslib](smallchesslib.md) Q_Q ~drummyfish }
 
-## Stats
+## Stats And Records
 
 Chess stats are pretty [interesting](interesting.md).
 
+{ Some chess world records are here: https://timkr.home.xs4all.nl/records/records.htm. ~drummyfish }
+
 **Number of possible games** is not known exactly, Shannon estimated it at 10^120 (lower bound, known as *Shannon number*). Number of possible games by plies played is 20 after 1, 400 after 2, 8902 after 3, 197281 after 4, 4865609 after 5, and 2015099950053364471960 after 15.
 
 Similarly the number of possibly reachable positions (position for which so called *proof game* exists) is not known exactly, it is estimated to at least 10^40 and 10^50 at most. Numbers of possible positions by plies is 20 after 1, 400 after 2, 5362 after 3, 72078 after 4, 822518 after 5, and 726155461002 after 11.
@@ -77,10 +79,17 @@ White wins about 38% of games, black wins about 34%, the remaining 28% are draws
 
 What is the **longest possible game**? It depends on the exact rules and details we set, for example if a 50 move rule applies, a player MAY claim a draw but also doesn't have to -- but if neither player ever claims a draw, a game can be played infinitely -- so we have to address details such as this. Nevertheless the longest possible chess game upon certain rules has been computed by [Tom7](tom7.md) at 17697 half moves in a paper for [SIGBOVIK](sigbovik.md) 2020.
 
-What's the most typical game? We can try to construct such a game from a game database by always picking the most common move in given position. Using the lichess database at the time of writing, we get the following incomplete game (the remainder of the game is split between four games, 2 won by white, 1 by black, 1 drawn):
+The longest game played in practice is considered to be the one between Nikolic and Arsovic from 1989, a draw with 269 moves lasting over 20 hours. For a shortest game there have been ones with zero moves; serious decisive shortest game has occurred multiple times like this: `1.d4 Nf6 2.Bg5 c6 3.e3 Qa5+` (white resigned).
+
+What's **the most typical game**? We can try to construct such a game from a game database by always picking the most common move in given position. Using the lichess database at the time of writing, we get the following incomplete game (the remainder of the game is split between four games, 2 won by white, 1 by black, 1 drawn):
 
 ```
-1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d4 exd4 6. cxd4 Bb4+ 7. Nc3 Nxe4 8. O-O Bxc3 9. d5 Bf6 10. Re1 Ne7 11. Rxe4 d6 12. Bg5 Bxg5 13. Nxg5 h6 14. Qe2 hxg5 15. Re1 Be6 16. dxe6 f6 17. Re3 c6 18. Rh3 Rxh3 19. gxh3 g6 20. Qf3 Qa5 21. Rd1 Qf5 22. Qb3 O-O-O 23. Qa3 Qc5 24. Qb3 d5 25. Bf1
+1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d4 exd4
+6. cxd4 Bb4+ 7. Nc3 Nxe4 8. O-O Bxc3 9. d5 Bf6 10. Re1 Ne7
+11. Rxe4 d6 12. Bg5 Bxg5 13. Nxg5 h6 14. Qe2 hxg5
+15. Re1 Be6 16. dxe6 f6 17. Re3 c6 18. Rh3 Rxh3
+19. gxh3 g6 20. Qf3 Qa5 21. Rd1 Qf5 22. Qb3 O-O-O
+23. Qa3 Qc5 24. Qb3 d5 25. Bf1
 ```
 
 You can try to derive your own stats, there are huge free game databases such as the Lichess [CC0](cc0.md) database of billions of games from their server.
@@ -120,7 +129,7 @@ Many other aspects come into the AI design such as opening books (databases of b
 
 The exact rules of chess and their scope may depend on situation, this is just a sum up of rules generally used nowadays.
 
-The start setup of a chessboard is following (lowercase letters are for black pieces, uppercase for white pieces, on a board with colored squares A1 is black):
+The start setup of a chessboard is following (lowercase letters are for black pieces, uppercase for white pieces (though many dislike this, for simplicity let's call pawns "pieces" too), on a board with colored squares A1 is black):
 
 ```
         _______________
@@ -138,7 +147,7 @@ The start setup of a chessboard is following (lowercase letters are for black pi
              files
 ```
 
-Players take turns in making moves, white always starts. A move consists of moving one (or in special cases two) of own pieces from one square to another, possibly capturing (removing from the board) one opponent's piece -- except for a special en passant move capturing always happens by moving one piece to the square occupied by the opposite color piece (which gets removed). Of course no piece can move to a square occupied by another piece of the same color. A move can NOT be skipped. A player wins by giving a **checkmate** to the opponent (making his king unable to escape attack) or if the opponent resigns. If a player is to move but has no valid moves, the game is a draw, so called **stalemate**. If neither player has enough pieces to give a checkmate, the game is a draw, so called **dead position**. There are additional situation in which game can be drawn (threefold repetition of position, 50 move rule). Players can also agree to a draw. A player may also be declared a loser if he cheated, if he lost on time in a game with clock etc.
+Players take turns in making moves, white always starts. A move consists of moving one (or in special cases two) of own pieces from one square to another, possibly capturing (removing from the board) one opponent's piece -- except for a special *en passant* move capturing always happens by moving one piece to the square occupied by the opposite color piece (which gets removed). Of course no piece can move to a square occupied by another piece of the same color. A move can NOT be skipped. A player wins by giving a **checkmate** to the opponent (making his king unable to escape attack) or if the opponent resigns. If a player is to move but has no valid moves, the game is a draw, so called **stalemate**. If neither player has enough pieces to give a checkmate, the game is a draw, so called **dead position**. There are additional situation in which game can be drawn (threefold repetition of position, 50 move rule). Players can also agree to a draw. A player may also be declared a loser if he cheated, if he lost on time in a game with clock etc.
 
 The individual pieces and their movement rules are: