Editing Losing chess (section)

==Analysis==
[[File:Suicide chess 1. d3 forced loss.gif|thumb|1.d3?? is one of several openings that lose by force: 1.d3 g5 2.Bxg5 Bg7 3.Bxe7 Bxb2 4.Bxd8 Bxa1 5.Bxc7 Bc3 6.Bxb8 Rxb8 7.Nxc3 d5 8.Nxd5 Nf6 9.Nxf6 Rg8 10.Nxe8 Rxg2 11.Bxg2 f6 12.Bxb7 Rxb7 13.Nxf6 h5 14.Nxh5 Rb1 15.Qxb1 Bb7 16.Qxb7 a6 17.Qxa6 {{chessAN|0–1}}]]
Because of the forced capture rule, losing chess games often involve long sequences of {{chessgloss|forced move|forced}} captures by one player. This means that a minor mistake can doom a game. Such mistakes can be made from the very first move—it is currently known that a Black win can be forced after 13 of White's 20 legal opening moves.<ref name=beasley>[https://www.jsbeasley.co.uk/losingopenings.htm Losing Chess openings : A summary of knowledge as at 10 October 2016] by John Beasley, for all but 1.Na3</ref><ref name=watkins>[http://magma.maths.usyd.edu.au/~watkins/LOSING_CHESS/ Losing Chess], Mark Watkins</ref> Some of these openings took months of computer time to solve: they vary greatly in difficulty. 

*The wins against 1.e4, 1.d4, and 1.d3 consist of simple series of forced captures and can be played from memory by most average players.{{efn|Solutions by [[David Bronstein]] were published in ''Popular Chess Variants'' (2000), pp. 33–34:
* '''1.d4??''' e5 2.dxe5 Qg5 3.Qxd7 Bxd7 4.Bxg5 Kd8 5.Bxd8 a6 6.Bxc7 Ra7 7.Bxb8 b6 8.Bxa7 a5 9.Bxb6 g6 10.Bxa5 Bb4 11.Bxb4 Ne7 12.Bxe7 Rf8 13.Bxf8 h6 14.Bxh6 g5 15.Bxg5 f6 16.Bxf6 Bh3 17.Nxh3 0–1
* '''1.d3??''' g5 2.Bxg5 Bg7 3.Bxe7 Bxb2 4.Bxd8 Bxa1 5.Bxc7 Bc3 6.Bxb8 Rxb8 7.Nxc3 d5 8.Nxd5 Nf6 9.Nxf6 Rg8 10.Nxe8 Rxg2 11.Bxg2 f6 12.Bxb7 Rxb7 13.Nxf6 Rb8 14.Nxh7 Rb1 15.Qxb1 Bb7 16.Qxb7 a6 17.Qxa6 0–1
* '''1.e4??''' b5 2.Bxb5 Nf6 3.Bxd7 Nxe4 and White loses no matter which capture is chosen:
** 4.Bxe8 Qxd2 5.Qxd2 (if 5.Bxf7 Qxc1 6.Qxc1 Nxf2 7.Kxf2 Rg8 etc.) 5...Nxd2 6.Kxd2 Rg8 7.Bxf7 c5 8.Bxg8 g6 9.Bxh7 e5 10.Bxg6 e4 11.Bxe4 Nc6 12.Bxc6 Bb7 13.Bxb7 Rc8 14.Bxc8 a6 15.Bxa6 c4 16.Bxc4 Ba3 17.Nxa3 0–1
** Or 4.Bxc8 Nxd2 5.Bxd2 Qxd2 6.Qxd2 Na6 7.Bxa6 Rc8 8.Bxc8 f5 9.Bxf5 Rg8 10.Bxh7 c5 11.Bxg8 e6 12.Bxe6 c4 13.Bxc4 a6 14.Bxa6 g5 15.Qxg5 Kd8 16.Qxd8 Be7 17.Qxe7 0–1}}
*The wins against 1.Nc3, 1.Nf3, 1.f4, and 1.h4 are harder to demonstrate, but can be solved by skilled players.<ref name=beasley/>
*The next tier of difficulty is formed by 1.b4, 1.c3, 1.f3, and 1.h3, which were solved by computers: they form a significant jump in difficulty from the previous set.<ref name=beasley/>
*1.a3 is much more difficult than those.<ref name=beasley/>
*1.Na3 is more difficult still.<ref name=watkins/>

In the table below, green marks winning first moves for White; red marks losing first moves; and yellow marks moves that are not yet solved.

{| class="wikitable" align="center"
|+ Status of White's twenty legal first moves
|-
| {{lost|Na3}}
|
| {{lost|Nc3}}
|
|
| {{lost|Nf3}}
|
| {{maybe|Nh3}}
|-
| {{maybe|a4}}
| {{lost|b4}}
| {{maybe|c4}}
| {{lost|d4}}
| {{lost|e4}}
| {{lost|f4}}
| {{maybe|g4}}
| {{lost|h4}}
|-
| {{lost|a3}}
| {{maybe|b3}}
| {{lost|c3}}
| {{lost|d3}}
| {{won|e3}}
| {{lost|f3}}
| {{maybe|g3}}
| {{lost|h3}}
|}

This main variant of losing chess was [[Solved game|weakly solved]] in October 2016; White is able to force a win beginning with 1.e3.<ref name=solve>{{cite web |last1=Watkins |first1=Mark |title=Losing Chess: 1. e3 wins for White|url=http://magma.maths.usyd.edu.au/~watkins/LOSING_CHESS/LCsolved.pdf |access-date=29 August 2017}}</ref> This solution is valid for both FICS and "International" rules on stalemate. Some lines are trivial (1...d6, 1...d5, 1...Na6, and 1...g6 lose in less than 20 moves), others are quite simple (1...Nf6, 1...h6, 1...e5, 1...f5, 1...h5, 1...f6, 1...a6, 1...a5 lose in less than 30 moves, subject to knowledge of the theory<ref name="solution">{{Cite web|url=https://antichess.herokuapp.com/|title=Antichess Solution Browser|access-date=2020-01-17|archive-date=2020-01-14|archive-url=https://web.archive.org/web/20200114233347/https://antichess.herokuapp.com/|url-status=dead}}</ref>), and some are quite complicated (1...Nh6, 1...Nc6, 1...c6, the win in which may require about 60 moves<ref name="solution" />). The most difficult are the following five openings<ref>{{Cite web|url=http://magma.maths.usyd.edu.au/~watkins/LOSING_CHESS/WEB/browse.php?e2e3|title=Mark Watkins's Solution Browser}}</ref> (in order of increasing difficulty): 1.e3 g5 (Wild Boar Defence), 1.e3 e6 (Modern Defence), 1.e3 b5 (Classical Defence), 1.e3 c5 (Polish Defence), and 1.e3 b6 (Liardet Defence).

[[David Pritchard (chess player)|David Pritchard]], the author of ''The Encyclopedia of Chess Variants'', wrote that the "complexity and beauty" of losing chess is found in its [[endgame (chess)|endgame]]. He noted that, in contrast to regular chess, losing chess endgames with just two pieces require considerable skill to play correctly, whereas three- or four-piece endgames can exceed human capacity to solve precisely.{{sfnp|Pritchard|2000|p=34|ps=}} For example, the following endgames may turn out to be quite complicated: ''2 Knights vs Rook'', ''3 Kings vs King'', or ''Bishop+Knight+King vs King''.<ref>{{Cite web|url=http://www.jsbeasley.co.uk/vchess/losingendlit.pdf|title=A first survey of Losing Chess endgame material published up to the end of 1999|last=Beasley|first=John|year=2000|website=The John and Sue Beasley WebSite}}</ref><ref>{{Cite web|url=http://www.jsbeasley.co.uk/vchess/losing3man.pdf|title=Three-man pawnless endings in Losing Chess|last=Beasley|first=John|year=1999|website=The John and Sue Beasley WebSite}}</ref> In the latter case, in particular, a win may require more than 60 moves, which means that it is sometimes unattainable due to the [[fifty-move rule]].