Chess960: Opening Puzzle no.11

Hit upon an interesting, exciting and unusual pawn gambit that makes a good little puzzle. The gambit is wonderful because white gives up a pawn and exposes his king to check yet still retains an excellent game.

SP493 e4!?
Assuming black accepts the gambit,
pick the square that makes this gambit
so promising for white.

The answer and the solution method is given below

 

 

 

Solution method:

Start by playing the obvious moves and study the state of the board:

1.        ...dxe4

2. fxe4...Qxe4+

3. Ne3...defending the check

 

With this board position, see that black's queen is attackable with initiative and that black's next move is not simple.

4.       ... f6?! (just any move for example)

 

Answer: The c6 square is white's most attacking square for the future after:

5. Bf3...Qe6

6. Nb4 and white is threatening to plant either a knight or bishop on c6.
Not only is c6 very weak for black, but white's overall development potential far exceeds the loss of the pawn.

Chess960: What is a logical first move?

In the previous post on viable first moves for SP395 Mark offered to play a match to try and find out the truth about what is a viable first move.Thanks for the match sounds like fun!

But before we start I have to clarify that the post was about viable first moves not logical first moves!

So if I reduce the viable list down to logical first moves, what are the list of logical first moves?

I think to decide that, we need to agree on why the center is so important in Chess960......

The center is fundamentally important in all 960 positions because of strategic flexibility.....the problem with Chess is that for at least a move you do not know what your opponent will commit to strategically. Therefore it is illogical to commit unnecessarily on either wing.

So the center (or possibly a flank) is the only place left to play....

Definition of wings, flanks and center:
Wings = a,b or g,h
flanks = c or f
center = d,e

So using that, a logical first move:

1. Doesn't break any tactical truths about the start (there usually aren't any)
2. Doesn't break any technical truths (as in moves that excessively slow down development)
3. Prefers playing out in the center for the sake of flexible strategy. That can include ANY move that controls the center either directly or indirectly. 
4. Doesn't play out knights unless they take some ownership of the center and/or there is a clear tactical theme that is generally beneficial in material or tempo.
5. Avoids committing to the wings because it commits to a specific strategy too soon. There may be a few exceptions to this where committing to a wing satisfactorily restricts the opponent in a very few start positions.
6. Doesn't castle straight away - there is no point revealing intentions so soon.

SP395: Eight logical first moves!?

SP395 is a great example because it includes 100% of all possible first moves in Chess960. So, despite that there are 16 viable moves, according to the above criterion for logic we get these logical moves (not ranked in any particular order):

1. c4 - yes because it takes some direct center control
2. d3 - yes because it is a direct center move
3. d4 - yes because it is a direct center move
4. e3 - yes because it is a direct center move enabling Nc1-e2
5. e4 - yes because it is a direct center move
6. g3 - yes because it is an direct center move
7. Nc3 - yes because it is a direct center move
8. Ne3 - yes because it is a direct center move

Rejected moves:

1. a3 - no because it commits to one wing too soon
2. a4 - no because it commits to one wing too soon
3. b3 - no because it is too vague (doesn't commit to the center either directly or indirectly)
4. b4 - no because it commits to one wing too soon
5. f3?! - no because it traps the bishop and weakens the king
6. g4 - no because it commits to one wing too soon.
7. Nb3 - no because it is too vague (doesn't commit to the center either directly or indirectly)
8. h3?! - no because it achieves too little
9. h4?! - no because it commits to one wing too soon
10. O-O?! - no because it makes little sense to reveal castling intentions so soon

Contested moves on technical grounds:

1. c3?! - problem is that it is technically not that good although it is an indirect center move. It is technically weak because it doesn't develop any pieces and probably commits to developmental congestion because keeping the c3 square clear is important developmentally.
2. f4?! - problem is that it is technically not that good although it is an indirect center move. It is technically weak because the only ownership right it makes to the center is to e5, a square that the opponent has no need to own.
3. Nd3?! - problem is that is technically not good. It takes control of center squares that the opponent need not own, and causes a potentially congested development.

Using the same logic we can compare SP395 with standard chess SP518:

SP518 {c4, d3, d4, e3, e4, f4, Nc3, Nf3} = 8 logical moves
SP395 {c4, d3, d4, e3, e4, g3, Nc3, Ne3} = 8 logical moves

Chess960: SP395 beats SP491 in the competition for the most number of viable starts

Turns out that SP395 beats SP491 in the competition to find the highest number of viable moves *here*. It beats standard chess in variety and also only takes four moves to castle queen-side like standard chess.

SP395: Sixteen viable first moves!?

Depth 24 search using Houdini-3 with a variation of only +/-0.15 for:

1. a3 - yes because it develops a queen
2. a4 - yes because it develops a queen, threatens a5 and controls b5
3. b3 - yes because it develops a queen and Nc3 shields the queen
4. b4 - yes because b4 is supported by Be1xb4 lining up black's king
5. c3 - yes because it shields the queen and enables d4
6. c4 - yes because it controls d5 and threatens c5
7. d3 - yes because it develops a bishop
8. d4 - yes because it develops a bishop and threatens d5
9. e3 - yes because it enables developing Nc1-e2
10. e4 - yes because it allows Ne3 and controls d5
11. f4 - yes because it develops a bishop and could support a pawn on d5
12. g3 - yes because it develops a bishop
13. g4 - yes because it develops a bishop (can white castle queenside!?)
14. Nb3 - yes because if 1...a5 white has a4/d3 attacking with development
15. Nc3 - yes because it is flexible and rapidly develops for sake of possible O-O-O
16. Ne3 - yes because it rapidly develops and controls d5

Rejected moves:

1. f3?! - no because it traps the bishop and weakens the king
2. Nd3?! - no because it over commits to a congested position
3. h3?! - no because it achieves too little
4. h4?! - no because it achieves too little
5. O-O?! - no because it makes little sense to reveal castling intentions so soon

I'm starting to think that the positions with queen in the corner and a bishop in the corner produce such massive first move choices because there is no compulsion for white to play out pawns into the center when it might be wise to keep the long diagonals open. Also, another possible reason is that both rooks are on the b-g files which supports pawns that could be useful all the way up to the 5th rank.

Chess960: Competition to find the SP with the highest number of viable first moves

Discovered a start position SP today that has a ridiculous amount of viable first moves options! More than standard chess in fact, fifteen in total. The absolute maximum number of first moves in some Chess960 starts is 21, but usually a large number of those can be ridden off because they are possible but theoretically too weak.

So here's the challenge.

See if you can find an SP that has more viable opening moves than this one:

SP491: 15 viable first moves

1. a3 - yes because it enables Qa2 developing the queen
2. a4 - yes because it enables Qa3 developing the queen
3. c3 - yes because it defends against Bh8 and allows d4
4. c4 - yes because it claims some center and can be supported by d3
5. d3 - yes because it develops a bishop
6. d4 - yes because it develops a bishop
7. e3 - yes because it allows Ne2/c3
8. e4 - yes because it claims some center and allows Ne2/c3
9. f4 - yes because it develops a bishop, controls g5 and threatens f5
10. g3 - yes because it develops a bishop
11. g4 - yes because it develops a bishop and is supported by a rook
12. h4 - yes because it takes control of g5, threatens h5 and allows Nh2/f3
13. Nb3 - yes because it controls d4
14. Nd3 - yes because it enables rapid castling
15. Ne3 - yes because it is flexible and developing

After a depth 24 search, Houdini-3 thinks that the variation in score between the best and worst first moves in that list is +/- 0.1 which is tiny. Realize that favoring a quick development of the corner bishop to attack the queen is not especially powerful and can be handled without problems.

In contrast, standard chess has at the very most 13 viable first moves but the variation in score is much bigger at +/- 0.43.

SP491 has a unique set of conditions with the queen in the corner allowing more options and a pair of knights that can be developed in a variety of ways. Also, the rooks support pawns that can be played out effectively. The only thing holding it back is less than optimal ways to develop the bishops. That opens the door for an SP which could possibly hit 16 viable first moves.

From my experience, I think SP491 could take the all time record. Prove me wrong!

Non-Random Chess960 Trial Game 9: SP864 after 4)...e6

Here is the continuation of a series of trial openings we are playing through for very difficult SPs that black must face. The PGN database for these trials including comments is here.

In this post we are going to take a look at SP864 in more detail considering that black really struggled in our initial Non-Random Trial game 9.

The move history up to this point was:
1. Ng3 Nf6 2. Nf5 Rg8 3. Nf3 Ng6 4. O-O e6

As can be seen, white has already castled and successfully prevented black from doing the same. Black's difficulties will be king safety and how to activate the rooks.

Mark has suggested that 4)...e6 might be a good way to solve many of black's problems. Not only does it push back the knight, it also potentially aids black's development and even possibly enables a square for black's king to temporarily sit. The problem is that the f6 square is weakened when it will come under fire from white's automatically fianchettoed bishop. The theory is that this will undermine black's king safety.

Most of the analysis we will do of this situation will be discussed in the comments to this post.

Initial position SP864: 4) ...e6

Non-Random Chess960 Trial Game 9: SP864

Here is the next in a series of trial openings we are playing through for very difficult SPs that black must face. The PGN database for these trials including comments is here.

Well for me personally, this SP number 864 was the toughest SP I have ever had to face playing the black side. I feel uncertain as to black's chances in this SP to draw and there would need to be more work done to convince me that black can find a draw (only my opinion please prove me wrong!)

The good news is that in practical play, black's opening moves are all principled and thus easy to commit to memory and white has to play very precisely otherwise all the initiative dissolves away. In any case even if black is in trouble in this SP, the game will play well beyond 25 moves. Therefore there is a lot of really interesting, creative and fun chess to be played in any case!

Not only is black's right to castle almost completely destroyed within only a few moves, but in this SP white's dark bishop sits in the corner readily deployed on the long diagonal firing at the kingside. Unlike our previous trial where the queen-side sequence was QBB, this time the queen sits on c1 in the classic "barbecue" BBQ arrangement (Weeks, 2012) and thus she has more freedom to move and exploit weaknesses from her c1 home.

Since we had already trialed the QBB version of this SP in trial 8, Mark found a very important improvement with 4.O-O. We both shared a kind of a laugh about our interpretations of this move! I thought of this early castling move as "super-solid" where I actually meant "aggressive". Mark thought I was implying that the early castling move was defensive. However please that it is not! After the castling move, white is free to gradually build up a very intimidating low risk attack on black.

The trial of this difficult SP concluded after 18 moves in some disagreement as to the likely outcome of the game. Mark chess expertise is significant. He gives black only a 10% chance of drawing after 18.d4. I think that this conclusion is harsh but it depends on a specific continuation starting with 18...Nd5 that produces a fascinating defense by black that we never got to play through unfortunately. So I present the hypothetical continuation after the 18th move just for fun.

SP864: How can black improve on this opening?

For me, I did not like this move I played:

SP864: Why 8...Nf4?!

Just from a question of logic, why threaten a pawn that requires white to respond in such a way that white's position is improved? Perhaps better was the immediate move 8...Qxc5. Black is actually trying to exchange off queens to take pressure of his king-side so that the king can lift to the seventh rank and finally connect the two rooks in a hybrid castling arrangement.

Since I feel uncertain about this opening by black 1.Ng3...Nf6, here is what I think might be a better opening:

SP864: An alternative opening idea

Black's idea is to give up another tempo to retain a king-side castling option and use the two military knights in the corner in a very challenging defensive setup that can protect the king. As we know, knights can be fantastic defenders if they are used well!

Chess960: Opening Puzzle No. 10

Whoa, more than a year since I posted the last Chess960 puzzle! Well to celebrate the tenth chess960 puzzle, here is a real beauty. This puzzle has some important theoretical significance once you understand it:

SP486: What is the most important reason why

 1.d4 is not a very good opening move by white?

The answer is surprisingly simple!

Enjoy the solution given below

The answer is (drumroll)...:

1. Because the long diagonal a8-h1 is weak!

If you thought the answer was:

2. Because the king is exposed along a5/e1, 
white can easily defend against that and 
continue development with moves like Bd2/Nc3.

Explanation:

1. d4   ... b6!(b5)

2. Nf3  ... Bb7 

And now white's f1 bishop is thematically trapped, 

since moving either e or g pawn results in:

3. g3?  ... Bxf3 followed by ...Qxf3

if instead:

2. e3?! ... Ba6!

3. Ne2  ... Bxe2

and 4.Kxe2 is essential because if:

4. Bxe2 ... Qxg2 -/+

Non-Random Chess960 Trial Game 8: SP868

The PGN database for these trials is here.

Our journey through the opening of SP868 has concluded. Incredibly on the second run through this opening black has found an absolutely perfect defensive setup despite all odds, and I as white was unable to crack it. Towards the end of the trial the position I was seeing on the board looked so powerful for white, but actually in the cold hard light of objectivity the position was equal. Here is the trial variation as we concluded. Check the database out for greater detail and comments.

Clearly white's moves were suboptimal. The most serious question marks are:

• 7. O-O?! white decides to try the same thematic castling idea that worked so well on our first trial run (see database)
• 9. Ba3?! a wasted tempo since black can match it with ...Bd6. White thought that ...Bxf5 where black drops the bishop pair would have to be good for white. However black didn't need both bishops to equalize.

SP868: Black's perfect defensive technique

An important heuristic in this fiendishly difficult SP:
Mark has come up with an excellent way of looking at this fiendishly difficult start, SP868. The idea is that black's apparent inability to castle is almost equivalent of being a pawn down. So black's strategy is to sacrifice a pawn and retain the ability to castle thus connecting the rooks and allowing more active play.

Sounds good! From what I am seeing of this SP, there is a serious game of cat and mouse at work. First strategy to rule out all together in my view, is for black to castle queenside, or to slide the king over to the queenside. Once white sees this strategy, they simply castle kingside and hit the queenside hard. Really hard. It might possibly work under special conditions as idea no.2 shows.

To me the strategy is for black to wait until white commits to the kingside, and then slide or castle the king to the kingside very carefully themselves. The combined QBB combination now tends to equalise, because both white and black's king will be the subject of their crossfire, with black's king a little less secure than white's.

Now that we are studying this SP in greater detail, here are a collection of ideas:

SP868 idea no.1: 1)...e6!?

The idea here is that the e7 square will become a temporary safe haven for black's king. It's worthy of some serious consideration!

SP868 idea no.2: ...2.Nh5!?

One of the fascinating things in the above variation is how the black king transfers over to the queen-side using the bishops and queen as protection rather than the traditional pawn shelter. (Note that 23.b5?! is met with  23...Nxe4!)

SP868 idea no.3: The Amazing Military Knight defenders!

One of the fascinating things about the above variation is how black manages to get the time to reorganise the Military Knights and how well they do as a cooperative unit. White still has an edge but black has a lot of play and the slightest slip from white and a lot of the advantage is gone.

Non-Random Chess960 Trial Game 7: SP749

The PGN database for these trials is here.

In this run through of SP749, the engines and CCRL database are indicating that white has a significant start advantage. Playing as white, I tried an early development of the queen. The idea did not work out all that well. Yes the queen can come out early in this SP because there are many squares that cannot be attacked. However, she is not all that effective unless well supported by other pieces. Here is a key moment:

SP749 trial: key moment

This is a key moment because white has pushed back black's knight to the back row, and I assumed that yet another move where black does not advance forward and develop, would have to be crippling. However, black's move 7....Qe8 simultaneously defending d7, attacking e5 and indirectly controlling the e-file was amazingly effective. White's queen is now without a target and she blocks the g1 bishop. White could play Nf3 but that would block the d1 bishop.

In this trial, I never solved the problem about what to do with the d1 bishop. Bg4 is obvious, but more difficult to achieve than I thought, since black has counter-play; the very thing I was trying to stop by the hyper rushed queen attack. Note that black's equivalent bishop on d8 can get to g5 but in black's case, there is no knight that impedes it's path there.

Good luck to the future generations of Chess960 players playing this SP as white or black. Is there a forced win for white? I think black could well be OK in this SP for at least a draw, but it is going to require memorization of the basic concepts, otherwise in practical play black will run out of time on the clock.