Timeline for Are there any illegal positions that are difficult to spot?
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 13, 2016 at 21:49 | comment | added | MarkH | Yes, I did mean ...d5. I see what you mean. In that case an illegal position could only arise when someone makes an illegal move and the opponent and arbiter let it stand. It's rare, but could happen. | |
| Sep 12, 2016 at 0:24 | comment | added | user2668 | In both of your lines, there's nothing on d5 for either player to take, so I assume you mean 5. ... d5 . With that change, for those lines, the castling issue only results in an illegal move, not an illegal position. | |
| Aug 23, 2016 at 2:09 | comment | added | MarkH | I don't know how to do a chessboard on here (sorta new), so here's some PGN: 1. d4 Nf6 2. c4 e6 3. Nf3 c6 4. e3 a6 5. Bd3 b5 6. cxd5 cxd5 7. O-O Bb4 The bishop may have appeared there with no check. 1. d4 Nf6 2. c4 e6 3. Nf3 c6 4. e3 a6 5. Bd3 b5 6. cxd5 cxd5 7. Qc2 Bb4+ 8. O-O The bishop does arrive with check and yet castling occurs (clearly illegal). | |
| Aug 21, 2016 at 21:09 | comment | added | David Schwartz | It's not at all obvious how you could construct an example of this. The castling may not have been the last move. | |
| Aug 21, 2016 at 16:33 | comment | added | seawalker | Thanks @MarkH. It would be great if you could add a real board as an example. | |
| Aug 21, 2016 at 15:33 | history | answered | MarkH | CC BY-SA 3.0 |