Chess960: Opening Puzzle no.12

Please don't hit me over the head with this next puzzle but enjoy it anyway!

  

SP510 white to play castling possible both sides:
What is white's best move here?

 Answer given below

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In chess960, you have to know the castling rules very precisely.
Although blacks bishop is hitting the b1 square, the passage of
the king for queenside castling is unaffected by the enemies
possession of that square.

Answer:
1.O-O-O hitting the d6 bishop in three ways

Chess960: Titular bishop strategy clarified

Well I've had a bit of encouragement to post again, because someone over at Reddit.com was kind enough to link to this site and the hits to this blog have spiked for a short moment in time.

 

If you are a reader of this blog, you know I love giving names to the bishop and knight pairs because it gives Chess960 more ways to distinguish between start positions. I think of the titular bishops as "bishops without a diocese" and even great players like Yasser Seirawan have been perplexed about how to deploy them (commentary from the Kings and Queens 960 tournament 2011).

 

So here is a discovery I have made about them which is relevant to a few dozen starting positions (SPs) in Chess960.

 

SP505: Pawn structure with titular bishops separating the king and queen

In this example, I've played out the position to show the basic strategy available to both players:

1. In SP505, the king is unlikely to castle queenside because four pieces have to be cleared out of the way.
2. The queenside is very heavy in pieces. The rook and queen team combine to allow a rapid space gain on the queenside by pushing pawns there (even the rook pawn).
3. The titular bishops are deployed to the queenside in the space made available, so that they form a powerful diagonal battery attack against the enemies king.
4. Now the queen switches between backing up either colour of bishop using the freed squares on the back rank, so that diagonal battery is at maximum strength.
5. The twist in the strategy is that white does not castle kingside and so does not give black this same strategic option.
6. The e-pawn is played to e3 so that it does not get in the way of the diagonal battery and the king plays to e2. This is safe, because white has gained so much queenside space that black cannot organise any kind of diagonal attack or knight attack against the king on e2.
7. Now white uses the kingside pawns as a storm front to break open blacks kingside defences to combine a crushing attack in combination with the bishop battery. The queenside rook is shifted across the back rank to aid in the kingside storm attack. 

Do you see this strategy? It works for black as well if white is not vigilant. The point is that when the king and queen are separated by the titular bishops in the middle, this strategy almost plays itself. In fact, I studied this SP in the LSS database only to find the rough sketch of this idea repeated a number of times.

 

Now I hear some critics of Chess960 say that this means that SP505 is relatively crude, because the strategy is so clear and potentially crushing. However, I looked at this SP in detail with Houdini-4, and I found that in fact, black has some amazing and efficient ways of undermining whites ideas. For example, check out the trial game of SP393 that Mark Weeks and I played with the titular bishops where black snuffed out this plan right out of the door!

 

So to me, the titular bishops in the combination [QBBK] or its mirror, are a wonderful study in how black efficiently prevents the strategy outlined here or deploys it themselves if white is clueless to it.

Who says that there is no theory or nothing to remember in Chess960 :-)

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