In this puzzle, I didn't even bother looking at material differences because it looks like white is in a mating net. Unless black is in check, who cares if white has an extra piece somewhere if black can force mate? I first looked at 20...Nf3+ and quickly dismissed it because black has destroyed any chances of mate or regaining the lost material. So then I turned to 20...Qxf2+ 21.Kxf2 (21.Kh1 Qg2#) and then I saw 21...Be3#. Then I double-checked the position to make sure it was really mate.

<Jack Bauer> is really helpful regarding weekdays....

On the emrald chess site, Q+B mate with criss-crossing diagonals occurs frequently enough that I would now call it a common mate. The analogies to Boden's mate (referred to below) help fix it in one's head.

I would see it with 5 sec on the clock

That is great! My main point was that it's a lot different looking at a puzzle knowing there is a win, and seeing the same position OTB with the clock ticking. I think I would see it but not in 5 seconds.

So when the opportunity arose with 20.Be2?, he probably jumped on 20...Qxf2+ with hardly any thought other than "whoopee!".

A brilliant crossfire mate.

20.Be2 was a horrible mistake. I have been looking at 20.Bg2 for white instead. While still leaving white in a bad position, it seems to stave off the immediate mate threat. Does anyone else see anything that I don't?

If this trend continues, I look forward to Wednesday's puzzle. A mate-in-one even I can't miss!

I think 17.Bg2 would be a whole lot better for White. Taking the rook off the open f-file weakened White's position considerably.

I think the advanced position of the K is what struck me about this position. Tha mating net is very efficient.

Very true. It also depends on the player's strength. For example, if you are rated around 1000 USCF it's not likely you will see this OTB because it involves "sac'ing the queen". But I can also see a 1400 or 1500 player missing this in an actual game. I've even seen experts miss easier tactics where they had plenty of time on the clock.

Once: My first thought was to play 20...Be3 21. Pass Qxf2+ 22. Kh1 Qg2# (or Bg2#).

Okay, so passing is not legal (and certainly not white's best defence). So can we take those elements and recombine them into a sequence that does work?

20...Be3 goes nowhere, so let's try 20...Qxf2+. Now it does not take long to spot that both 21. Kh1 and 21. Kxf2 allow mate in 1.

Nice one.

Now, let's try to defend for white instead of the lemon 20. Be2? Let's try 20. Bg2 Bg4 21. Qb1 Nf3+ 22. Bxf3 Qxf3 23. Qd1 Qxd1 24. Rad1 Bxd1 25. Rxd1 Rxb2

click for larger view

White isn't mated, but is the exchange down and has a grim position to defend.

However, there are several true Boden's Mates in the database, including the original Boden's Mate. They're collected here: Game Collection: Boden's Mate. Boden's Mate can often involve queen sacs. I just recently won a local chess club tourney game by recognizing the almost exact same pattern as Alekhine vs Vasic, 1931 in a game opening with the French Winawer.

btw, I agree way too easy for Wednesday, more likely a Tuesday

<Nullifidian thanks so much for linking to the collection of Boden's Mates>

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