Saturday, March 26, 2011

Chess960: SP362

Well what do you say about Chess960?! It just keeps on surprising! Still we have not found any seriously flawed starting position yet (where white's advantage is so great that it destroys a sense of competition). This starting position is an an example of a really interesting starting position that has knights in the corners and rooks that hug the king. Please Chess960 simplifiers, don't take this position out of your reduced set!

Over at Mark has highlighted SP362 as one of those SP's that contains what you can say is a "prickly pawn". A prickly pawn is a pawn that causes an immediate pricking sensation for white if he grabs it, followed by slow bleeding :-). The amazing thing is that after a shallow 16 ply (8 moves) analysis in Rybka4-960 of all 18 possible first moves for white, at best white's evaluation is in the range {+0.07...-0.25}!

SP362 - The Prickly Pawn
Firstly here is the variation that Mark played in a real live game scenario. It contains a nice tactic that Rybka4-960 finds:
1. f4 d5!     Black gives up the a7 pawn
2. Qxa7 Nb6   Black get's compensation...
3. Qa3 Ra8 
4. Qb3 e6 
5. a3 Bd6     White's move could well be required
6. Bf2? Nc4!  White's knight outpost is stable!
7. e3? Rxa3!! A nice rook sacrifice!
8. bxa3 Bxa3+ 
9. Rb2 Bxb2+ 
10.Kb1 Bf6 
11.Bxc4 dxc4 
12.Qxc4 Bc6   Black has a winning position

Ok let's get to the crunch question, why is the a7 pawn a "prickly pawn" for white. The simplest explanation is that because of black's structure Nb6/Ra8, white's queen must retreat after the capture. However no matter where the queen goes, she either comes under attack down the track or obstructs white's development from there. For example one queen sequence is:

SP362 - The Flight of the Knight
The red squares show how white's queen must retreat and subsequently block further development and also waste tempo. That amount of waste is a serious penalty for the material gain of the a7 pawn. So the conclusion is that black doesn't have to protect the prickly pawn! 

With that question answered, what possible replies does black have to 1.f4? If you notice, even 1...Ng6 is possible! Yes believe it or not....

Get this! Black has a stable outpost for a knight on c4 that is continuous across many variations! When you think about it, the c4/c5 outposts are there from the start for a number of reasons:
  1. b3/b6 to stop Nc4/c5 is bad
  2. d3/d6 to stop Nc4/c5 blocks the f1/f8 bishop
  3. A knight on c4/c5 can go to a3/a6 and stay there
  4. The enemy knights cannot dislodge a knight on c4/c5
  5. Exchanging the f1/f8 bishop for a knight on c4/c5 is dubious
  6. c4/c5 can quickly be protected with Qg1/g8 and Bf2/f7
  7. c4/c5 is a quickly accessible location for the a1/a8 knight
Here is an extreme example:
1. f4   Ng6!?   What the??
2. f5   Ne5!?   What the??
3. d4   Nc4!?   The knight is stable on c4!
4. e4   d5!     Rybka4-960 is happy for black!

SP362 - The amazing knight outpost swindle!
What do you say about that! Chess960 is amazing. Ridiculously funny at times and quite tragic at others! I'm sorry but I have to take a break this is making me laugh too much. You would think that white is doing ok but Rybka4-960 likes the position for black even at 13ply with a score variation of {1. Bxc4 -0.30...10. Bd3 -0.63}. I've seen this phenomenon before in 960. The amazing swift and majestic knight! Here is the water torture continuation:
5. exd5 b5!    Black prepares a rook lift down the track
6. b3?  
White can't shake off that knight without troubles because the knight becomes stable on a3. Essentially you can ask the question what is black's knight going to do on a3, but the answer is not what it is going to there, but what is white's knight going to do on a1!


  1. Here's a blogging tip: if you link to a specific post on another blog, rather than to that blog's home page, the other blog's software picks up the incoming link and adds an automatic link to the specific post you referenced; the automatic link points back to the referencing post. That way you get targeted links between the two pages and, hopefully, some additional visitors to your own blog. - Mark