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# Chess # Chess
Chess is an old two-player board [game](game.md), perhaps most famous and popular among all board games in history. It is a [complete information](complete_information.md) game that simulates a battle of two armies on a 64x64 board with different battle pieces. Chess has a world-wide competitive community and is considered an intellectual sport but is also a topic of active research (chess is unlikely to be ever solved due to its non-trivial rules combined with enormous state space, Shannon estimated the number of possible games at 10^120) and programming (many chess engines, [AI](ai.md)s and frontends are being actively developed). Chess is an old two-player board [game](game.md), perhaps most famous and popular among all board games in history. It is a [complete information](complete_information.md) game that simulates a battle of two armies on a 64x64 board with different battle pieces. Chess has a world-wide competitive community and is considered an intellectual sport but is also a topic of active research (as the estimated number of chess games is bigger than [googol](googol.md), it is unlikely to ever be solved) and [programming](programming.md) (many chess engines, [AI](ai.md)s and frontends are being actively developed).
{ There is a nice black and white indie movie called *Computer Chess* about chess programmers of the 1980s, it's pretty good, very oldschool, starring real programmers and chess players, check it out. ~drummyfish } { There is a nice black and white indie movie called *Computer Chess* about chess programmers of the 1980s, it's pretty good, very oldschool, starring real programmers and chess players, check it out. ~drummyfish }
@ -15,8 +15,6 @@ Chess is an old two-player board [game](game.md), perhaps most famous and popula
- It is a source of many interesting [mathematical](math.md) and programming challenges. - It is a source of many interesting [mathematical](math.md) and programming challenges.
- It seems to strike the right balance of simplicity and complexity, it is very simple but not so trivial as to be ever solved in a foreseeable future. - It seems to strike the right balance of simplicity and complexity, it is very simple but not so trivial as to be ever solved in a foreseeable future.
What is the longest possible chess 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.
## Chess In General ## 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).
@ -53,6 +51,24 @@ 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 } { Nanochess is actually pretty strong, in my testing it easily beat [smallchesslib](smallchesslib.md) Q_Q ~drummyfish }
## Stats
Chess stats are pretty [interesting](interesting.md).
**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 possible reachable positions 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.
Shortest possible checkmate is by black on ply number 4 (so called *fool's mate*). As of 2022 the longest known forced checkmate is in 549 moves -- it has been discovered when computing the Lomonosov Tablebases.
Average game of chess lasts 40 moves. Average [branching factor](branching_factor.md) (number of possible moves at a time) is around 33.
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.
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.
## Variants ## Variants
Besides similar games such as [shogi](shogi.md) there are many variants of chess, i.e. slight modifications of rules, foremost worth mentioning is for example chess 960. The following is a list of some variants: Besides similar games such as [shogi](shogi.md) there are many variants of chess, i.e. slight modifications of rules, foremost worth mentioning is for example chess 960. The following is a list of some variants:

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@ -4,6 +4,12 @@ OpenArena (OA) is a first person arena shooter [game](game.md), a [free as in fr
As of version 0.8.8 there are 45 maps and 12 game modes ([deathmatch](deathmatch.md), team deatchmatch, [capture the flag](ctf.md), last man standing, ...). As of version 0.8.8 there are 45 maps and 12 game modes ([deathmatch](deathmatch.md), team deatchmatch, [capture the flag](ctf.md), last man standing, ...).
A bit of [fun](fun.md): you can redirect the chat to text to speech and let it be read aloud e.g. like this:
```
openarena 2>&1 | grep --line-buffered ".*^7: ^2.*" | sed -u "s/.*: ^2\(.*\)/\1/g" | sed -u "s/\^.//g" | espeak
```
Character art exhibits what [SJWs](sjw.md) would call high sexism. This is great, it's the good old [90s](90s.md) art style. The art is very nice and professional looking (no programmer art). Characters such as Angelyss are basically naked with just bikini strings covering her nipples. Other characters like Merman and Penguin (a typical "[Linux](linux.md) user") are pretty funny. Ratmod has very nice taunts that would definitely be labeled offensive to gays and other minorities nowadays. The community is also pretty nice, free speech is allowed in chat, no [codes of conduct](coc.md) anywhere, [boomers](boomer.md) thankfully don't buy into such bullshit. Very refreshing in the politically correct era. Character art exhibits what [SJWs](sjw.md) would call high sexism. This is great, it's the good old [90s](90s.md) art style. The art is very nice and professional looking (no programmer art). Characters such as Angelyss are basically naked with just bikini strings covering her nipples. Other characters like Merman and Penguin (a typical "[Linux](linux.md) user") are pretty funny. Ratmod has very nice taunts that would definitely be labeled offensive to gays and other minorities nowadays. The community is also pretty nice, free speech is allowed in chat, no [codes of conduct](coc.md) anywhere, [boomers](boomer.md) thankfully don't buy into such bullshit. Very refreshing in the politically correct era.
OpenArena is similar to e.g. [Xonotic](xonotic.md) -- another free arena shooter -- but is a bit simpler and oldschool, both in graphics, features and gameplay. It has fewer weapons, game modes and options. However there exist additional modifications, most notably the Ratmod (or RatArena) which makes it a bit more "advanced" (adds game modes, projectiles go through portals, improved prediction code etc.). As of 2022 an asset reboot in a more Anime style, called OA3, is planned and it seems to be aiming in the right direction -- instead of making a "modern HD game" (and so basically just remake Xonotic) they specifically set to create a *2000 game* (i.e. keep the models low poly etc.). It could also help distinguish OpenArena from Quake more and so make it legally safer (e.g. in terms of [trade dress](trade_dress.md)). OpenArena is similar to e.g. [Xonotic](xonotic.md) -- another free arena shooter -- but is a bit simpler and oldschool, both in graphics, features and gameplay. It has fewer weapons, game modes and options. However there exist additional modifications, most notably the Ratmod (or RatArena) which makes it a bit more "advanced" (adds game modes, projectiles go through portals, improved prediction code etc.). As of 2022 an asset reboot in a more Anime style, called OA3, is planned and it seems to be aiming in the right direction -- instead of making a "modern HD game" (and so basically just remake Xonotic) they specifically set to create a *2000 game* (i.e. keep the models low poly etc.). It could also help distinguish OpenArena from Quake more and so make it legally safer (e.g. in terms of [trade dress](trade_dress.md)).