The opening book is made from nearly a quarter of a million games
from the last ten years with both players rated 2300 and up. The
stats next to moves are how many games resulted in wins draws or
losses. The concept originated from computer opening books as if we
can open up the book and see the moves that people play in response
to chess opening positions.
The analyze button on bottom of app is to flip between viewing the
openings move table or seeing Stockfish engine analysis. +1.00
score means white is ahead a pawn. -1.00 score means black is ahead
a pawn. There is a move button to make the engine make the current
best move and this can be used to play a line out.
In the Actions menu PGN game files can be opened. The app also
comes with some installed PGN files on Open App's PGN menu item. To
ensure speed in loading it will only read/load a max of 2500 games.
With bigger files users will only see first 2500.
There is a Save Board to PGN option on the menu. It saves the
current moves to a file OpeningTree will create on first save. .
This allows the users to move data out of the app with the mail
games button available in the game list view. Games are saved with
white and black players names named after the opening such as
Sicilian vs Sicilian or QGD etc.
While users do not pick the openings they study ahead of time they
start with all the first moves in the tree such as e4 d4 and Nf3
arranged by most winning after making a few moves the opening name
will display below the board such as King's Gambit or French
Defense to alert the user what opening they have moved
into.