Here's Jirakon's cook:The position becomes legal upon removal of any unit:
[fen]7k/pp1p1K1P/7r/7P/7P/7P/7P/B7[/fen]
White pawns must have made at least 10 captures. Bc8 was captured at home, bringing the total to 11. White's last move was Kf6xBf7, preceeded by Bg6-f7+ (there is no other way to cancel the check from bRh6). This makes 12 white captures, which is one too many. (continued below)
Removing Ba1 or Rh6 eliminates one of the "problem" checks, and White need not capture Bf7. Removing a wP reduces the number of White captures. Removing a bP provides an extra unit for White to capture.
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Here's the new version of the problem. There is one less wP to place, so hopefully that takes care of "too many captures" cooks.
SwissGambit, Original
Add both Kings, 4 wP, 3 bP, 1 bR to create an Illegal Cluster.
Illegal Cluster: An illegal position that becomes legal if any piece is removed from the board (besides the Kings).
Originally posted by JirakonThere are several solutions.
Before I attempt the new variation, I wanted to submit my new puzzle.
Black 1
[fen]5Q2/Q7/1Q6/4Q3/7Q/2Q5/3Q4/6Q1 w - - 0 1[/fen]
White 9
Place the two kings on the board to create a legal position, or prove that this position is illegal regardless of where the kings are.
1) +bKc8, +wKc6(5,4). Retract -1.g7xf8Q+ etc.
2) +bKb1, +wKb3(4,5). Retract -1.Qxg1+ etc.
In fact, almost any square where bK is checked by only 2 Q works. Just block one check with wK, and have the other Q retract check (and uncapture something if needed to give Black something to move).
Ok, that one ended up worse than I expected (I actually had a thrid solution; see if you can find it). This puzzle started much differently. I guess in all my messing with it, it got cooked. Here's what it started as:
Black 1
White 9
Again, the last move did not involve a capture. The puzzle is still to place the two kings on the board so that the position is legal, or else prove that the position is illegal regardless of the kings' positions.