# The Tree window

The Tree window displays information on all the moves made from the current position in games in the database. In tree mode, the tree window is updated automatically whenever the main windows board changes. This can be slow for large databases.

Note that whenever the tree window is updated, the filter is reset and only the games that contain the current position will be included.

Clicking the left mouse button on a move in the tree window adds that move to the game.

### Tree window contents

The tree window shows the ECO code (if any), frequency (both as number of games, and a percentage) and score of each move. The score is always computed from the White perspective, so 100% means all White wins and 0% means all Black wins.

The moves in the tree window can be sorted by move (alphabetically), ECO code, frequency, or score. You can change the sort method using the [Sort] menu.

### Best games window

The tree window has a File menu command and button for opening the Best games window, which shows a list of the highest-rated games in the currently displayed tree branch. The games are listed in order of average rating, and you can restrict the list to show games with a particular result.

### Tree graph window

The tree window buttons include a button marked Graph which produces a graphical display of the relative performance of each move from the current position. All moves that have been played at least 1% of the time, and at least 5 times, are displayed. Percentage scores are always from White's perspective even when it is Black to move.

In the tree graph, a red line is plotted showing the mean over all games from the current position, and the area between 50 and 55% (where most standard openings are expected to score) is colored blue to assist comparison of moves. Note that white usually scores around 55% in master level chess.

### Locking the tree window

The Lock button in the tree window can be used to lock the tree to the current database. This means the tree will continue to use that database even when you switch to another open database. This is useful if you want to use a large database as a reference while playing through a game in another database: simply open the tree on the reference database, lock it, then switch to the other base.

### Training

When the Training checkbox in the tree window is selected, Scid will randomly make a move every time you add a move to the game. The move Scid chooses depends on database statistics, so a move played in 80% of database games will be chosen by Scid with 80% probability. Turning on this feature, then hiding (or iconifying) the Tree window and playing openings against a large database, is a great way to test your knowledge of your opening repertoire.

### Using the Tree with EPD files open

For each open EPD file, the tree window will contain an extra column that shows a short (five character) summary of the contents of the EPD file for each position reached from the moves listed.

The summary could be an evaluation, an opening code or a suggested move; it will be the contents of the first EPD field found from the following list: ce, eco, nic, pv, pm, bm, id, or just the first EPD field if none of the above are present.

For a description of EPD fields, see the EPD file help page. Note that if the summary is of the ce field, it is shown as an evaluation in pawns from Whites perspective (rather than as a score in centipawns from the perspective of the side to move, which is its stored format in the EPD file) for improved readability.

### Caching for faster results

Scid maintains a cache of tree search results for the positions with the most matching games. If you move forward and back in a game in tree mode, you will see the tree window update almost instantly when the position being searched for is in the cache.

The tree window has a file menu command named Save Cache. When you select this, the current contents of the tree cache in memory are written to a file (with the suffix .stc) to speed up future use of Tree mode with this database.

The Fill cache file command in the file menu of the tree window fills the cache file with data for many opening positions. It does a tree search for about 100 of the most common opening positions, then saves the cache file.

Note that a tree cache (.stc) file is completely redundant; you can remove it without affecting the database, and in fact it is removed by Scid whenever an action occurs that could leave it out of date -- for example, adding or replacing a game, or sorting the database.

(Updated: Scid 3.0, November 2001)