After 22.NF7+ Kg8, 23.Nxe5+ Rf7, 24. Nxd3. Why was this a blunder?
Why did the engine call this discovered check and queen capture a blunder?
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bkellog1
Nov 24, 2019
0
#1
Nov 24, 2019
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#3
First of all, well played. That was a nice tactic. Did you look at the rest of the computer analysis? When it says a move is a blunder, you can always look at what the computer recommends as a response, which will generally show you why it’s bad, or not as good as an alternative. In this case it doesn’t say that either “blunder” is losing for you, but that it gives up a large portion of your advantage. For Nf7+, black could have played Rxf7. After the discovered check, the computer recommends taking the bishop with the queen.
Nov 24, 2019
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#4
Instead of Nf7+ the computer recommended Rb3, where the queen is forced to either sacrifice itself or you start a mating attack with Qh5.
ARKelly1996 wrote:
Instead of Nf7+ the computer recommended Rb3, where the queen is forced to either sacrifice itself or you start a mating attack with Qh5.
Rb3, as strong as it is, is still not the best move.
ARKelly1996 wrote:
Instead of Nf7+ the computer recommended Rb3, where the queen is forced to either sacrifice itself or you start a mating attack with Qh5.
22. Rb3 was pretty terrible move of Stockfish at low depth.
I was really surprised why Stockfish 10 couldn't find checkmate in low depth but she found it after 60 seconds in my Samsung phone.
22. Qh5 f4 22. Re4 Qxb1+ 23.Be1 h6 24. Qg6 hxg5 25. Qh7##
I will check later how fast Stockfish 11 developmental version can see it.
In retrospect, Rb3 might actually be also good, but not for the given reasons. Many lines in the analysis above involve Black holding on longer by using the queen to guard h7. Thus Qxb3 allows Qh5! anyways and this time Black gets mated within 2-3 moves. Still, 22.Rb3 allows 22...g6, getting Black out of imminent danger. Even a free queen after 23.Rxd3 isn't as good as the clear forced mate given by 22.Qh5!.
bkellog1 wrote:
Specifically, it calls 22.NF7+ a blunder and 23.Nxe5+ as a mistake.
As for why 23.Nxe5+ is a mistake, why get a queen for two pieces when you can get one for one piece? 23...Qxd5 24.cxd5 Nxe5 gets Black two pieces for the queen whereas 23.Ng5+ gets a queen for one piece (23...Qxd5 24.cxd5 and this time the knight is safe), since 23...Kh8? loses to 24.Qh5 as above.
blueemu wrote:
22. Qh5 h6 23. Qg6 hxg5 24. Qh5 mate
You missed 22. Qh5 f4( defending Queen)
Queen can be blocked , it is mate in 6, not mate in 3.
Nov 24, 2019
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#11
Interesting. Thanks all! This was the first time I've posted in the forums and I really appreciate the analysis.
bkellog1 wrote:
Interesting. Thanks all! This was the first time I've posted in the forums and I really appreciate the analysis.
I have two tips for you to improve:
- Read Murray Chandler’s How to Beat Your Dad at Chess, which covers this basic pattern (Greco’s Mate). Only after reading this book and his Chess Tactics for Kids should you use Tactics Trainer, since you should be aware of these patterns and pattern recognition first. Even after you see a good move...
- ...find another. Nf7+ is not losing but had you looked just a little further you could’ve just knocked your opponent out right away.
Nov 24, 2019
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#14
WindowsEnthusiast wrote:
bkellog1 wrote:
Interesting. Thanks all! This was the first time I've posted in the forums and I really appreciate the analysis.
I have two tips for you to improve:
- Read Murray Chandler’s How to Beat Your Dad at Chess, which covers this basic pattern (Greco’s Mate). Only after reading this book and his Chess Tactics for Kids should you use Tactics Trainer, since you should be aware of these patterns and pattern recognition first. Even after you see a good move...
- ...find another. Nf7+ is not losing but had you looked just a little further you could’ve just knocked your opponent out right away.
Appreciate the advice and just ordered it. Thank you!
Nov 24, 2019
0
#15
drmrboss wrote:
blueemu wrote:
22. Qh5 h6 23. Qg6 hxg5 24. Qh5 mate
You missed 22. Qh5 f4( defending Queen)
Queen can be blocked , it is mate in 6, not mate in 3.
I didn't miss it. I just gave the "main variation", the one that illustrates the theme. Only engine monkeys feel that the longest line is the most important one.
blueemu wrote:
drmrboss wrote:
blueemu wrote:
22. Qh5 h6 23. Qg6 hxg5 24. Qh5 mate
You missed 22. Qh5 f4( defending Queen)
Queen can be blocked , it is mate in 6, not mate in 3.
I didn't miss it. I just gave the "main variation", the one that illustrates the theme. Only engine monkeys feel that the longest line is the most important one.
Well, if you think the opponent dont defend at all , a chess game can end up in 4 moves.
1. e4 a6
2. Qf3 a5
3. Bc4 a4
4. Qxf7##
Playing your idea only without considering opponent's resources is always flawed.
Engine analysis always help that human flaws.
drmrboss wrote:
blueemu wrote:
drmrboss wrote:
blueemu wrote:
22. Qh5 h6 23. Qg6 hxg5 24. Qh5 mate
You missed 22. Qh5 f4( defending Queen)
Queen can be blocked , it is mate in 6, not mate in 3.
I didn't miss it. I just gave the "main variation", the one that illustrates the theme. Only engine monkeys feel that the longest line is the most important one.
Well, if you think the opponent dont defend at all , a chess game can end up in 4 moves.
1. e4 a6
2. Qf3 a5
3. Bc4 a4
4. Qxf7##
Playing your idea only without considering opponent's resources is always flawed.
Engine analysis always help that human flaws.
For the OP in this case, knowing that Greco’s Mate was the right idea is the main point and that like helps deliver it.
Nov 24, 2019
0
#18
WindowsEnthusiast wrote:
For the OP in this case, knowing that Greco’s Mate was the right idea is the main point and that like helps deliver it.
Exactly. That's why I just showed the main variation (the Greco mate) instead of confusing the (1200 rated) OP with a tree of analysis.
How come the engine does not find a mate in 6, while in other cases can find a mate in 8?
zlatkod168 wrote:
How come the engine does not find a mate in 6, while in other cases can find a mate in 8?
Do you know how many possible positions in search tree in mate in 6?
If you ask an engine to do brute force search, the number of possible positions in mate in 6 is
30^11= 17,000 trillions. Yes it is 1.7 e+16.
Stockfish can search 5 million positions per second in common 4 cores CPU. 1 min search is 300 million positions only and it will take about 10 years
to find the checkmate.
However, thanks to powerful search priority algorithm in Stockfish 10( checkmate, capture materials etc) , Stockfish 10 found in one minute in my phone. It means it search millions time faster than a brute force in this position.
In case Stockfish search algorithm can be improved with the advance in Neural Network, Stockfish 20 probably find the mate in < 10 seconds.