| 1 | p.boxed |
| 2 | | White plays one move, then black play twice, |
| 3 | | then white plays three moves... |
| 4 | |
| 5 | p. |
| 6 | At the very first move of the game, white make only one move - as usual. |
| 7 | However, after that and for all the game, each side must play as many moves |
| 8 | as the opponent just played plus one. |
| 9 | |
| 10 | p. |
| 11 | If a move gives check, then the sequence stops here, but the opponent can |
| 12 | still play as many moves as would be theoretically possible. |
| 13 | Also, if a checkmate or stalemate situation occurs before the maximal number |
| 14 | of moves are played, the game ends. |
| 15 | There are no en-passant captures. |
| 16 | |
| 17 | figure.diagram-container |
| 18 | .diagram |
| 19 | | fen:rnbqk2r/pppp2pp/4p3/8/1b1P4/4pN2/PPP1PPPP/RN1QKB1R: |
| 20 | figcaption "Mate in 1" |
| 21 | |
| 22 | p. |
| 23 | On the diagram white mates with the sequence of 5 moves c3 Ne5 Qd3 Qf5 Qf7. |
| 24 | Moves' notation is replaced by ∞ (infinity) when there are four moves |
| 25 | or more to print. |
| 26 | |
| 27 | h3 More information |
| 28 | |
| 29 | p |
| 30 | | You can start from the |
| 31 | a(href="https://en.wikipedia.org/wiki/Progressive_chess") |
| 32 | | Wikipedia page |
| 33 | | , which points to |
| 34 | a(href="http://users.ics.aalto.fi/tho/chess.html") this page |
| 35 | | with several commented games. |