# White mates in 3

BigDoggProblem
Posers and Puzzles 27 Mar '05 07:28
1. 28 Mar '05 07:071 edit
Originally posted by ilywrin
Pretty obvious, since white king has moved (the rook at d4 must have come from h1) so 1.Rad1!
What's to stop the d4 rook coming from a1?

If 1. Rad1? then Black castles.
2. 28 Mar '05 07:101 edit
Originally posted by THUDandBLUNDER
No, it's not.
What was Black's last move?
Ke8, Rh8 or g6

and if black can castle, it was g6
3. 28 Mar '05 07:11
Originally posted by Jusuh
Ke8, Rh8 or g6

and if black can castle, it was g6
See the bishop at b8 it must have gooten there through h6 so g6 was played before ðŸ™‚
4. 28 Mar '05 07:151 edit
Originally posted by THUDandBLUNDER
What's to stop d4 rook coming from a1?

If 1. Rad1? then black castles.
Well, let's look at the last two moves of both sides shall we?
White's may have been any (they cannot castle either way since either the rook at d4 came from h1, so the king moved, or it came from a1 so the king again moved and the rook also).
Black's last move can only be
2...b6, the previous therefore must be a capture (or move) to either d4 or a1 for him to be able to castle.
EDITED: Capture at e6 or promotion at e1 also spotted.
I will think a bit more to find what prevents Black from castling but the solution is in any case 1.Rad1!
5. 28 Mar '05 07:15
Originally posted by THUDandBLUNDER
White to play and mate in 2 moves.

[fen]4k2r/p1p1p1p1/1p2P3/8/3R4/6P1/5P1P/R3K3[/fen]
1.O-O-O! ... 2.Rd8#
6. 28 Mar '05 07:21
Originally posted by ilywrin
See the bishop at b8 it must have gooten there through h6 so g6 was played before ðŸ™‚
ilywrin, have you heard about under-promotion. ðŸ™‚ pawns can be promoted not only queens, but to rooks, knights and bishops too.
7. 28 Mar '05 07:291 edit
Originally posted by Jusuh
ilywrin, have you heard about under-promotion. ðŸ™‚ pawns can be promoted not only queens, but to rooks, knights and bishops too.
Quite true ðŸ™‚ I have forgotten about that ðŸ™„

Anyway the only possible places to promote a black bishop of the respective colour would be g1 and c1 and seeing the position as it is there must have been two captures, one with check, so white king must have moved so White cannot castle.
And also White must take care of the black bishop on the f8 (missing in the final position). The only possible way through underpromotion would be through Ng(e)6 x f8 which however I cannot find impossible.
8. 28 Mar '05 07:372 edits
This mate-in-3 puzzle is based on the same idea as the mate-in-2 I subsequently posted.
9. 28 Mar '05 07:492 edits
THUDandBLUNDER perhaps you would care to expalin to someone not as good in the retrograde problems as yourself?
EDITED: or is it that the condition of the problem cannot be met if Black can castle?
10. 28 Mar '05 07:58
Originally posted by ilywrin
See the bishop at b8 it must have gooten there through h6 so g6 was played before ðŸ™‚
OK, I am getting too old for this. What is wrong with the following premises (as a possibibility):
- the last two moves were a7 by white and g6 by black
- black can castle, meaning that
--- the bishop on f8 was captured before by a white knight
--- the bishop on b8 is a promoted one, a pawn promoting on g1 (black's d-pawn, after capturing two other pieces/pawns). The bishop came to b8 via a7, before the white pawn was there.
- white cannot castle (because the king must have moved, either before or at the moment the black pawn came to f2)

That would mean no solution, since Rd1 would be followed by 0-0.
11. 28 Mar '05 08:10
Originally posted by Mephisto2
OK, I am getting too old for this. What is wrong with the following premises (as a possibibility):
- the last two moves were a7 by white and g6 by black
- black can castle, meaning that
--- the bishop on f8 was captured before by a white knight
--- the bishop on b8 is a promoted one, a pawn promoting on g1 (black's d-pawn, after capturing two other pi ...[text shortened]... t the black pawn came to f2)

That would mean no solution, since Rd1 would be followed by 0-0.
See my previous posts, I have totally agreed with that but THUDandBLUNDER insists that there's a solution.

My only reasoning in this case is that since the condition of the problem cannot be met if Black can castle he shouldn't be able to, in order to have a solution ðŸ™‚
12. skeeter
515 + 30 days
28 Mar '05 08:20
Originally posted by Jusuh
1.O-O-O! ... 2.Rd8#
Incorrect. White is unable to castle. How did the h file rook get out if the King did not move?

skeeter
13. 28 Mar '05 08:231 edit
Originally posted by ilywrin
See my previous posts, I have totally agreed with that but THUDandBLUNDER insists that there's a solution.

My only reasoning in this case is that since the condition of the problem cannot be met if Black can castle he shouldn't be able to, in order to have a solution ðŸ™‚
HINT:

Can you prove that White can't castle?
Can you prove that Black can't castle?
Can you prove that not both can castle?

14. 28 Mar '05 08:343 edits
Very well, Jusuh is right then. To the 2 mover:
The rook at d4 was promoted so White plays 1.O-O-O! and Black has moved his rook or king (due to the promotion) so he can't castle.
The same to the 3 mover. Only this time black bishop is not promoted, so last move isn't g6 ðŸ™‚
So, by castling White denies the Black the option of castling and the problem is resolved ðŸ™‚
Hehehe, this was educational ðŸ˜‰
15. 28 Mar '05 08:45
Originally posted by THUDandBLUNDER
HINT:

Can you prove that White can't castle?
Can you prove that Black can't castle?
Can you prove that not both can castle?

isn't it sufficient that there is no proof that black lost his castling right? Apart from a flaw in my set of premises (which I hope you will show us if that is the case), then I think we cannot exclude black castling and hence, escape from mate in 3.