14 Sep 2026

The Opening Library

Chessou has a repertoire section now. It's a big one, and it runs on the same idea as the rest of the site: your own games decide what you work on.

The repertoire section is desktop only for now. Phone and tablet are coming soon.

The Opening Library: 21 repertoires built for your rating

Pick an opening and you get a full repertoire for it, built from the games players at your rating actually play. Every reply you'll face is covered.
They're built on 56 to 87 million games from players at those ratings.
Each comes in three sizes: around 30 lines for Beginner, 70 for Intermediate, 250 and a lot deeper for Advanced.
Most opening courses you can buy are built off master games. You rarely get those lines at your level. The repertoires in Chessou are built off the games people at your level really play.
Not sure which one to take? "What fits me?" asks you a few questions and puts the ones that suit you in front of you.
Take one and it's yours. Change a line, cut what you don't want, add your own.
Learn it move by move, then send the lines to your training.

The builder is connected to your chess account, so your repertoire is built around the games you actually play. What goes in is still up to you.
The lines you face most get done first, so you don't spend too much time on something you'll see once a year.
If you want, it can also pull from games at your rating and cover lines you haven't met yet.
It stays connected while you keep playing. As soon as your games show a weak spot in the repertoire, it tells you, and you can fix it right away.
An opening course is finished the day it's written. Yours keeps up with whatever people start playing against you.

Openings fade when you haven't touched them for a few weeks. The trainer brings each one back just before that happens, and the gaps get longer every time you get it right.
You play the whole line through, move for move, not single positions pulled out of context.
The lines that need work turn up in your daily training on their own. There's no queue to manage.

The bot plays the opponent side and answers with the replies in your repertoire.
Which lines come up depends on how often you face them in your own games. You can also point it at one line and work on that.
When your repertoire ends, the bot keeps playing the moves players at that rating really play. Set it to 1400 and you get 1400 moves.
Survival mode is about how far you can get without a single slip. Play a line clean and the next one comes straight at you. One move outside the book and the run is over. Best runs go on the leaderboard.

A new drill made out of the moves you played too quickly and got wrong. Not the hard positions you sat and thought about, the ones you rattled off without looking.
One drill type for the chance you rushed past, one for what you handed your opponent.

Plus around 25 smaller changes: puzzle combos, a rebuilt game review, and a few things around streaks.