What Were the Last Few Moves?

Originally posted by THUDandBLUNDER
[fen]4nb1k/p1pppK1B/1p3pp1/8/8/8/8/8[/fen]

I don't see why this is hard.

Retract: -1...Ng7-e8 -2.Ke8-f7 N~g7+ -3.Kd8-e8 etc.

White King leaves via b7 and a6, White Bishop leaves via g8 to a2, and the position unwinds.

Edit: there must be something missing, because the last moves aren't forced.

Sorry, I knew I should have checked the position before logging off.
There is a Black pawn on g7.

Originally posted by THUDandBLUNDER
Sorry, I knew I should have checked the position before logging off.
There is a Black pawn on g7.

[b][fen]4nb1k/p1pppKpB/1p3pp1/8/8/8/8/8[/fen][/b]

-1.Bg8xQh7 Q~xNh7 -2.Ng5-h7 Q~ -3.h7xRg8=B Q~ -4.h6-h7 and now wP steps back, bK and bR leave the NE corner, wK to g8, bNe8 to d6, and wK exits via b7, etc.

Again, I don't see why this is forced, because on Black's first retraction, his Queen can come from several different squares on the h-file, and he simply uses the Queen to 'pass' later on.

Originally posted by BigDoggProblem
-1.Bg8xQh7 Q~xNh7 -2.Ng5-h7 Q~ -3.h7xRg8=B Q~ -4.h6-h7 and now wP steps back, bK and bR leave the NE corner, wK to g8, bNe8 to d6, and wK exits via b7, etc.

Again, I don't see why this is forced, because on Black's first retraction, his Queen can come from several different squares on the h-file, and he simply uses the Queen to 'pass' later on.

Good analysis, BigDogg.

But I'm not sure what your beef is.
At what point could Black 'pass' with his queen?

Originally posted by THUDandBLUNDER
Good analysis, BigDogg.

But I'm not sure what your beef is.
At what point could Black 'pass' with his queen?

My beef is with the stipulation. It should not ask "what were the last several moves?" when only one of them can be determined exactly. A better and more common stipulation is to "resolve the position", meaning to retract moves until you reach a point of obvious legality.

Let me explain the notation I use. "Q~" means Queen-any, meaning the queen can be moved to many legal squares. So if you look closely at my notation, Black's first retracted move is not accurate (could be several squares that the Q came from), and his 2nd and 3rd retracted moves are 'pass' moves with the Queen while waiting for White to do stuff.

Originally posted by BigDoggProblem
My beef is with the stipulation. It should not ask "what were the last several moves?" when only one of them can be determined exactly. A better and more common stipulation is to "resolve the position", meaning to retract moves until you reach a point of obvious legality.

OK, I will be more careful with thread titles in future (or you will be on my case).