What are the improvements of Fritz 11?

[Uri Blass]

Hi Ludovic

Surprising and disappointing results. You have demonstrated that fritz 11 is not always better than fritz 10, and indeed it is a quite different engine.

So if f11 with null move unchecked, gained points solving zugzwang positions but in the end got less points, I suppose that means that did not solve even more positions that were found before, can you post these unsolved positions?

I see nothing surprising about the results
I think that the results is what you could expect.
There is no reason to expect non default setting to perform better than the default setting when it is clear that not all endgames are about zugzwang detection.

Uri

[mercury]

I just wanted to see if pruning wasn't too radical with null move on. In the previous version Fritz 10 there is not the possibility to desactivate null move so there was no question.

[Oscar L]

Hi Ludovic

Thanks for testing fritz 11 with null move disabled. And thanks for these particular positions.

I tried them with and without null move and this is what I got; not your settings though, 128 MB HT and 3-4 men tablebases installed, but consistent


Fritz 11 default

1 Nf7+ +- (2.14) Depth: 20/45 00:00:28 65347kN

2 Ke3 +/- (0.93) Depth: 14/26 00:00:02 5628kN

3 e4 +- (4.55) Depth: 21/41 00:00:35 79704kN, tb=3919

4 Qg5 +- (3.25) Depth: 15/35 00:00:13 30451kN, tb=873

5 g6 +- (1.66) Depth: 20/38 00:00:25 53516kN

6 Qf6+ +- (2.13) Depth: 21/42 00:00:34 66877kN, tb=2677

7 Rc8+ +- (2.41) Depth: 22/41 00:01:02 133mN



Fritz 11 null-move off

1 Nf7+ +- (2.14) Depth: 20/47 00:04:28 628mN, tb=75

2 Ke3 +/- (0.79) Depth: 18/33 00:02:43 362mN, tb=156

3 e4 +- (4.51) Depth: 20/39 00:01:00 151mN, tb=10800

4 Qg5 +- (3.27) Depth: 17/36 00:10:45 1542mN, tb=77483

5 g6 +- (1.91) Depth: 22/45 00:14:01 1914mN

6 Qf6+ +- (2.01) Depth: 21/42 00:14:10 1754mN, tb=24182

7 stopped, not found after 24 minutes

[Oscar L]

You are right Uri

This is what chessbase states in the help file:

Use Nullmove: The Null Move is a special search mechanism which reduces the size of the search
tree, so that the engine can look deeper. If one side makes two moves in a row ("null move" for
opponent) and does not get a big advantage, the engine assumes that the first move is bad. This is
usually highly efficient. However in certain endgame positions it can overlook Zugzwang.