9/15/2011 - Mate in 9


freshbacon & lycanwerewolf PROO


I was surprised I got the first 3 moves correct.


Too easy for Thursday




Clever puzzle.


You have to start off with your Knight in order to free a path up for your Bishop.  If you start off with your Rook, then you pretty much come to a dead end.  Black has an option to capture your Knight with his pawn, but that willl only lead to a Mate in 3.  After that, all of the moves are forced and Black's fate is sealed.


The following is a copy of Post #155 on Page 8 by @elindauer:

I take decisions in these puzzles exactly the way I play OTB.  My goal is to find the best move with the least amount of calculation.  In this case, I solved the puzzle in 3 steps:


phase 1: calculating forcing lines

- check material, see that white is winning.

- start calculating forcing lines.  My first glance was Rd7+ Kb8 Rxg7.  I evaluate this as winning for white but not resignable yet.  This becomes my main line.

- consider other forcing checks / captures.  I happened to look at Nb5+ next.  First I tried Nb5+ cxb5 Rd7+.  The king has a couple choices, I tried Kb8 Be5+ Ka8 and ran into a wall.  I evaluate this as worse then my main line and discard it.  I note that letting the king get to a8 kills my attack, and try Nb5+ cxb5 Be5+ Kc6.  I look for forcing continuations, and see Rc3+, Bd7+ ... oh, Bd7+ Kc5 Bd6#... is mate!  ok.  So Nb5 cxb5 wins for white.


Now I looked at Nb5+ Kb8 Bd4+ Ka8 Nc7+ Kg8.  I can see that Ne6+ here wins the exchange, and I already evaluate this as better than my main line.  So I cut off my calculation and call this my main line.


Return to calculating forcing lines in the original position... Nd5+ cxd5 ... wait, no, Nd5+ Kb8 transposes to the main line and this is black's option.  No need to calculate Nd5+ cxd5 since black will only play this if it worse for me then my main line.  Ignore.


So I am ready to move.  I go to the puzzle and play Nb5+ Kb8 Be5+ Ka8 Nc7+.


Phase 2: where to put the knight.

- from phase 1 I already have a main line: Ne6+ Ka8 Nxc8.  I extend a little farther and see Rxc8 Bxg7 picking up another pawn too.  I evaluate this as totally winning for white.  In time trouble I would play this instantly.  With a few minutes to spare, I calculate the alternatives:

- Na6+ Ka8 and I see nothing better then just Nc7+ repeating moves.  Discard.

- Ne8+... aha this allows Rd8... Ka8 Rd8+ Bc8 Rxc8+ Kb7.  I can't stop calculating just yet since the knight is pinned.  However I see that Rc7+ followed by Ne6 will save the knight.  Since I prefer to win the bishop then to win the exchange, and I can see that there is still some life in this line left to calculate, I evaluate this as better then Ne6+ and continue...

- Rd8+ Rxd8... Ne6+... nothing really coming to mind here.  I am ready to move.

So I go to the puzzle and play Ne8+ Ka8 Rd8+ Bc8 Rxc8+ Kb7.


Phase 3: calculating the win.

Same song, different verse.  I know that I have Rc7+ and just save the knight, with a winning 3 minor pieces vs a rook endgame.  I calculate a few more forcing lines to see if there is a mate:

- Nd6+ is nice, only 1 answer... Ka6... Bf1+ b5... Bxb5+ cxb5 Rc6+ Ka5... seems promising but I'm not quite seeing the knockout.  I put this under "consider again later" and return to other ideas

- Rb8+ Ka6 Bc8+ Kb5 I have h5+, f5+... oh wait, I see that Rb8+ Ka6 Nc7+ only allows Ka5... now Bc3+... is mate!  ok I'm ready to play.


Rb8+ Ka6 Nc7+ Ka5 Bc3 winner winner chicken dinner.


So this mate in 9 can be taken over the board as three different 3 move combinations.  You don't have to see the whole thing up front to solve it.  Hope that helps.




A very clever puzzle, even though I need someone to fully analyze it to spot why cxb5 isnt good of an answer


long drawn out.


nice one especially the first move of knight


good one


long but nice puzzle


good one!


I became unstuck with this puzzle as there is no Queen to sacrifice.


Nice one.




I like when the king is under pressure.


AasTmO wrote:

A very clever puzzle, even though I need someone to fully analyze it to spot why cxb5 isnt good of an answer

hi  AasTmO,

if cxb5 then Be5+ Kc6, Bd7+ Kc5, Bd6#


yup great puzzle... :)