Implement shogi Issue 1508Shogi

docs/games.md

@@ -86,6 +86,7 @@ Status                                                                 | Game
 ❌ ([#811](https://github.com/google-deepmind/open_spiel/issues/811))   | Reconnaissance Blind Chess                                                                     | 2       | ✅              | ❌            | Chess with opponent's pieces unknown, with sensing moves. Chess variant, invented by John Hopkins University Applied Physics Lab. Used in NeurIPS competition and Hidden Information Game Competition. References: [Markowitz et al. '18, On the Complexity of Reconnaissance Blind Chess](https://arxiv.org/abs/1811.03119). [Newman et al. '16, Reconnaissance blind multi-chess: an experimentation platform for ISR sensor fusion and resource management](https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9842/984209/Reconnaissance-blind-multi-chess--an-experimentation-platform-for-ISR/10.1117/12.2228127.short?SSO=1).
 🟢                                                                      | Routing game                                                                                   | 1+      | ✅              | ✅            | Players choose at each node where they go. They have an origin, a destination and a departure time and choose their route to minimize their travel time. Time spent on each link is a function of the number of players on the link when the player reaches the link. References: [Cabannes et. al. '21, Solving N-player dynamic routing games with congestion: a mean field approach](https://arxiv.org/pdf/2110.11943.pdf).
 🔶                                                                      | Sheriff                                                                                        | 2       | ✅              | ❌            | Bargaining game. Good for correlated equilibria. Based on the board game [Sheriff of Nottingham](https://boardgamegeek.com/boardgame/157969/sheriff-of-nottingham). References: [Farina et al. '19, Correlation in Extensive-Form Games: Saddle-Point Formulation and Benchmarks](https://papers.nips.cc/paper/9122-correlation-in-extensive-form-games-saddle-point-formulation-and-benchmarks.pdf).
+🔶                                                                      | [Shogi](https://en.wikipedia.org/wiki/Shogi)                                         | 2       | ✅              | ✅            | Chesslike game where captured enemy pieces can be dropped into the game as one's own.
 🔶                                                                      | [Slovenian Tarok](https://en.wikipedia.org/wiki/K%C3%B6nigrufen#Slovenia)                      | 3-4     | ❌              | ❌            | Trick-based card game with bidding. References: [Luštrek et al. 2003, A program for playing Tarok](https://pdfs.semanticscholar.org/a920/70fe11f75f58c27ed907c4688747259cae15.pdf).
 🔶                                                                      | [Skat](https://en.wikipedia.org/wiki/Skat_\(card_game\)) (simplified bidding)                  | 3       | ❌              | ❌            | Each turn, players bid to compete against the other two players.
 🔶                                                                      | [Solitaire (K+)](https://en.wikipedia.org/wiki/Klondike_\(solitaire\))                         | 1       | ❌              | ❌            | A single-player card game. References: [Bjarnason et al. '07, Searching solitaire in real time](http://web.engr.oregonstate.edu/~afern/papers/solitaire.pdf).

open_spiel/games/CMakeLists.txt

@@ -190,6 +190,10 @@ set(GAME_SOURCES
   rbc/rbc.h
   sheriff/sheriff.cc
   sheriff/sheriff.h
+  shogi/shogi.cc
+  shogi/shogi.h
+  shogi/shogi_board.cc
+  shogi/shogi_board.h
   skat/skat.cc
   skat/skat.h
   solitaire/solitaire.cc
@@ -667,6 +671,10 @@ add_executable(sheriff_test sheriff/sheriff_test.cc ${OPEN_SPIEL_OBJECTS}
                $<TARGET_OBJECTS:tests>)
 add_test(sheriff_test sheriff_test)
 
+add_executable(shogi_test shogi/shogi_test.cc ${OPEN_SPIEL_OBJECTS}
+               $<TARGET_OBJECTS:tests>)
+add_test(shogi_test shogi_test)
+
 add_executable(skat_test skat/skat_test.cc ${OPEN_SPIEL_OBJECTS}
                $<TARGET_OBJECTS:tests>)
 add_test(skat_test skat_test)

open_spiel/games/crazyhouse/crazyhouse_board.cc

@@ -652,8 +652,6 @@ Square CrazyhouseBoard::find(const Piece& piece) const {
 
 void CrazyhouseBoard::GenerateLegalMoves(const MoveYieldFn& yield,
                                          Color color) const {
-  // We do not need to filter moves that would result for King to move / stay
-  // in check, so we can yield all pseudo legal moves
   if (king_in_check_allowed_) {
     GeneratePseudoLegalMoves(yield, color);
   } else {