by Steve Lopez

In last week's ETN, we examined several engine output displays available in ChessBase 8. We'll look at some more options in this week's issue.

The first is a variation board mode:

You can activate the variation board by right-clicking in the engine window and selecting "Variation board" from the popup menu. The size of the variation board will vary with the size of the engine pane (see ETN, October 1, 2000 for more information on moving and resizing panes). The purpose of the variation board is to allow you to play through the best variation the engine has found thus far in its search.

You'll notice a set of VCR buttons below the variation board; these are your controls for playing through moves on this board. You can step forward and backward through the variation one move at a time by using the single arrow VCR buttons. If you want to jump right to the beginning or end of a variation, you can use the double arrow buttons for that purpose.

Last week, we looked at a way to scroll the variations an engine finds, showing you its "thoughts" at each successive ply depth. In some cases, this may cause the analysis window to scroll very quickly because of the amount of information provided. A way to cut down on the volume of info is to right-click in the engine analysis pane and select "Scroll new moves only". This will provide a slightly different display -- a new variation will be displayed only if it contains information different from the last variation shown in the window:

In the example to the right, take a look at the last variation in the display (the one beginning with 26.Qe3). We see that at a nine-ply search depth, Fritz6 found the variation to be better for White by 1.03 pawns. Instead of showing the same variation again (as we saw in last week's issue) at an eleven-ply depth, it simply shows the new evaluation: 1.28 pawns in White's favor. Although the numeric evaluation has changed, the moves themselves remain the same; Fritz hasn't found any improvements for either side.

"Scroll new moves only" eliminates some of the redundancy in the display when the scrolling option is selected. When the engine has a new numerical evaluation of the position, but the actual moves of the variation haven't changed, only the new numerical evaluation is displayed. Information doesn't scroll off the top of the display as quickly, plus there's the added benefit of being able to more readily see where in the search the analysis actually changed. In the example, we see that Fritz changed its mind (from 26.Rxb3 to 26.Qd2) during the first ply of the analysis. 26.Qd2 remained the preferred move until the fifth ply of the search, when it was replaced by 26.Qc1. After a deeper look into the position, we see Fritz switch to 26.Qg3 in the seventh ply and alter its evaluation yet again to 26.Qe3 during the ninth ply of the search.

One of the features of ChessBase's playing programs is the ability to show threats (ETN, May 9, 1999). This function is also available for most chess engines in the engine pane of ChessBase 8. Just start the analysis engine and hit the "x" key on the keyboard:

In essence, what this does is reverse the moving side. For example, in the actual game it's White's turn to move. But hitting x makes the engine think it's Black's turn to move again and shows you where the threat lies (after all, by definition, a threat is what a player could do if he could make two moves in a row). In the example, we see that Black is threatening to capture on g5 (White's piece on g5, by the way, is his Queen), resulting in a huge swing in Black's favor (evaluated at a 10.03 pawn advantage).

Note, too, that the panel showing the name of the engine has turned red. This is to remind you that the analysis pane is in "Show threat" mode. To return to the normal analysis mode, just hit the x key a second time.

Yet another analysis display mode is "Next best". When you show multiple lines of analysis in the display (as described in last week's ETN), you might sometimes see a "second best" move that looks really interesting. Hitting the "y" key on the keyboard causes the display to hide the best line of play and show just the second-best line of play (and the resulting evaluation). This saves some processing time (the computer won't have to update both the best and second best lines of play on the screen) and will thus allow a slightly quicker analysis of that second-best variation. To turn off "Next best", hit y a second time.

Note, too, that you can combine "Show threat" and "Next best". Hit x to start "Show threat" and then hit y. You'll now see the "second-best threat" in that position. Hit x and y again to turn off these display modes.

The variety of display modes we've examined over the last two weeks provides you with a lot of tweakable options, allowing you great flexibility in the information you receive from the chess engines; this flexibility should lead to greater understanding of the positions you examine in ChessBase 8.

Until next week, have fun!

You can e-mail me with your comments, suggestions, and analysis for Electronic T-Notes.