Just a quick Fritz12 tip today, based on a previous post to this blog. If you haven’t yet read last week’s “Casual games in Fritz12”, go have a look, then hit your browser’s “back” button to c’mon back here when you’re finished.
In that prior post, I yammered the following:
If, on the other hand, you set Fritz12 for a Fixed Depth (let’s say you set it for a value of 14, meaning seven moves for both sides) it will always move after finishing a fourteen ply (half-move) search, no matter what, even if it’s a complicated position in which further search may well be deserved. It’s really up to you (and the next Fritz12 tip will concern a trick for using Fixed Depth), but I’m more inclined to use Fixed Time rather than Fixed Depth.
In addition to what I wrote above, here’s why I don’t like “Fixed Depth” (and this is the “next Fritz12 tip” I mentioned)…
The “Fixed Depth” setting requires the user to be a little more knowledgeable and careful than does “Fixed Time”. This is because improperly setting the “Fixed Depth” value can cause Fritz12 (or any other chessplaying program) to become tactically “blind”. This is best described by an abstract example.
Let’s say that you’ve set a “Fixed Depth” value to “12”, which would equate to six moves for both sides. Fritz12 is playing White, you’re playing Black. You get to a certain middlegame position with White to move. Fritz looks at and evaluates every possibility out to a depth of six moves for each player (with each variation ending with Black’s sixth move). It finds the variation with the best evaluation in White’s (Fritz’) favor and plays that move, starting that variation.
The problem is that the final (Black) move in that variation set up an unpreventable Knight fork in which Black wins major material. Since the “Fixed Time” value was set to an even number, which means the analysis was cut off with a Black move, Fritz never sees that the last move sets up that big-time catastrophe on Black’s seventh move. So Fritz blindly goes about its merry way — and later gets hammered by that Knight.
Had the “Fixed Time” value been set to “13” instead, the analysis would have allowed Fritz to look ahead one more ply (to White’s seventh move) to see how it could have avoided Black’s tactical shot.
Now I’ll grant you that’s a very rough example; if I was a smarter person I could likely have come up with something better. But I think it serves to illustrate an important tip for using Fritz12 (or any other chessplaying software) — and the tip applies not just to playing games but also to analyzing games as well:
When setting a value for “Fixed Depth” for either play or analysis, always set the value to an odd number to prevent the software from exhibiting a tactical “blind spot”.
It’s a very simple thing, but important things very often are that simple. You’ll get much better results from your chessplaying software if you remember and follow that tip.
Have fun! — Steve