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End-game evaluation
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Evert Glebbeek



Joined: 21 Jan 2011
Posts: 892
Location: NL
PostPost subject: Re: End-game evaluation    Posted: Mon Oct 10, 2011 1:04 pm Reply to topic Reply with quote
hgm wrote:

In Spartan Chess the two lightest pieces of the Spartans (Captain and Lieutenant) have both color-changing and color-preserving moves, and both have a value close to that of Knight/Bishop. So in Spartan Chess you can have a situation where the Persions, with BPP, have difficulty to overcome a defence bya single C or L staged purely on the other color than the Bishop, the Captain only using its (2,0) moves, and the Lieutenant only the (1,1) and (2,2) moves, after they switched to the right color. So these end-games could have the same drawishness as that of unlike Bishops in orthodox Chess, easily fencing off a majority of 2 Pawns.

Sjaak has some startup-logic to determine whether pieces are colour bound and it has a term for them in the evaluation. I think it mainly uses it to give a pair bonus, but I've certainly thought about a few generalised endgame evaluation terms (mainly, keep the king away from the corner of a colour bound piece, but also considering an edge pawn with a promotion square on the colour of the piece to be slightly better).
I don't remember whether I took the Lieutenant's colour-changing ability into account or not. I think I deliberately didn't, because I thought a pair bonus would be good for them, but of course I didn't have the resources to test this idea.
I'm very interested in the idea of colour-weakness, and I think I could make it an important evaluation term in Sjaak (maybe not Jazz, where I can use much more game-specific evaluation terms), but I don't seem to have found a form for the evaluation term that actually works...

Quote:
For the Spartans, and in Berolina Chess, which uses the same Pawns that capture straight and move diagonally, another interesting phenomenon occurs. Pawns become effectively color-bound (as long as they don't capture), and you could get into positions where the color-bound Bishop cannot hinder them at all, because they are on the other color. They just march on to promotion. So the concept 'bad Bishop' can take on dramatic dimensions, the Bishop becoming virtually worthless as a defender (other than being a sink of moves to avoid zugzwang).

The berolina pawns certainly seem to become dangerous passers much more easily. I find them hard to evaluate in an ending.
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Subject Author Date/Time
End-game evaluation H.G.Muller Tue Oct 04, 2011 11:44 am
      Re: End-game evaluation Evert Glebbeek Tue Oct 04, 2011 1:02 pm
            Re: End-game evaluation H.G.Muller Tue Oct 04, 2011 2:20 pm
      Re: End-game evaluation Oliver Uwira Tue Oct 04, 2011 1:59 pm
      Re: End-game evaluation Jon Dart Tue Oct 04, 2011 2:10 pm
            Re: End-game evaluation Jon Dart Tue Oct 04, 2011 2:13 pm
      Re: End-game evaluation Kevin Hearn Tue Oct 04, 2011 8:19 pm
            Re: End-game evaluation Pawel Koziol Wed Oct 05, 2011 10:46 am
      Re: End-game evaluation H.G.Muller Mon Oct 10, 2011 8:09 am
            Re: End-game evaluation H.G.Muller Mon Oct 10, 2011 9:00 am
                  Re: End-game evaluation Evert Glebbeek Mon Oct 10, 2011 1:04 pm
                  Re: End-game evaluation Ed Schroder Mon Nov 07, 2011 10:15 pm
            Re: End-game evaluation H.G.Muller Wed Oct 19, 2011 10:16 am
                  Re: End-game evaluation Michael Hoffmann Wed Oct 19, 2011 11:48 am
                        Re: End-game evaluation H.G.Muller Wed Oct 19, 2011 1:24 pm
                              Re: End-game evaluation Michael Hoffmann Wed Oct 19, 2011 2:53 pm
                                    Re: End-game evaluation Volker Annuss Wed Oct 19, 2011 4:53 pm
                                    Re: End-game evaluation H.G.Muller Wed Oct 19, 2011 4:54 pm
                                          Re: End-game evaluation H.G.Muller Sat Oct 22, 2011 5:29 pm
                                                Re: End-game evaluation H.G.Muller Mon Nov 07, 2011 7:28 pm
                                                      Re: End-game evaluation Evert Glebbeek Mon Nov 07, 2011 8:33 pm
                                                            Re: End-game evaluation Evert Glebbeek Mon Nov 07, 2011 9:02 pm
                                                                  Re: End-game evaluation H.G.Muller Mon Nov 07, 2011 9:40 pm
                                                            Re: End-game evaluation H.G.Muller Tue Nov 08, 2011 11:16 am
                                                                  Re: End-game evaluation Evert Glebbeek Tue Nov 08, 2011 5:50 pm
                                                                        Re: End-game evaluation H.G.Muller Tue Nov 08, 2011 8:16 pm
                                                                              Re: End-game evaluation Evert Glebbeek Tue Nov 08, 2011 8:52 pm
                                                                                    Re: End-game evaluation H.G.Muller Tue Nov 08, 2011 10:14 pm
                                                      Re: End-game evaluation Karlo Bala Jr. Mon Nov 07, 2011 11:59 pm
                                                            Re: End-game evaluation H.G.Muller Tue Nov 08, 2011 7:30 am
                                                                  Re: End-game evaluation Kevin Hearn Tue Nov 08, 2011 9:58 am
                                                                        Re: End-game evaluation H.G.Muller Tue Nov 08, 2011 12:40 pm
                                                                              Re: End-game evaluation Evert Glebbeek Tue Nov 08, 2011 5:53 pm
      Re: End-game evaluation Mark Lefler Mon Oct 10, 2011 4:08 pm
            Re: End-game evaluation H.G.Muller Mon Oct 10, 2011 9:09 pm
                  Re: End-game evaluation H.G.Muller Mon Oct 10, 2011 9:58 pm
                  Re: End-game evaluation H.G.Muller Tue Oct 11, 2011 8:50 am
                        Re: End-game evaluation H.G.Muller Tue Oct 18, 2011 6:36 pm
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