Train for Your Opponents: Game Sync for Chess.com and Lichess
You've built a solid repertoire. You've got lines against the Sicilian Najdorf, the French Defense, the Caro-Kann, even some obscure sidelines in the Scotch Game. Your spaced repetition queue is humming along. But there's a problem: you keep drilling the Najdorf, and in your last 30 games, not a single opponent played 1...c5. They all played 1...e5.
This is the gap between studying theory and studying what you'll actually face. Most players build a repertoire based on what's theoretically important, which is fine as a starting point. But your training time is limited, and not every line deserves equal attention. The lines your opponents play every day should get more reps than the ones you see once a year.
That's why we built Game Sync.
What Is Game Sync?
Game Sync connects your Chess.com or Lichess account to Openings.gg. It fetches your recent games (last 30 days), compares the openings your opponents played against your repertoire, and boosts the matching lines to the front of your next training session.
Here's the flow:
- Connect your Chess.com username or Lichess account on your profile page
- Click "Sync Games"
- Openings.gg analyzes your recent games and matches them against your repertoire
- Lines that match get boosted — they become due immediately and appear before everything else in your next drill session
- You see a summary of which lines were boosted and how many games matched
Why This Matters
You have limited training time
Say you have 200 lines in your White repertoire. On any given day, maybe 20 are due for review. That's a 10-minute session. But if 15 of those are deep sidelines in the King's Indian that nobody at your rating plays, and 5 are mainline responses to the Italian Game that you see three times a week, the default scheduling treats them equally.
Game Sync fixes this. The Italian lines get boosted to the front of the queue. You drill the positions you'll actually see in your next game before touching the theoretical sidelines.
Your opponents don't play like theory books
At 1200, nobody plays the mainline Najdorf. At 1600, you'll face the Stafford Gambit more than the Marshall Attack. At 2000, you start seeing more refined move orders. The lines worth drilling depend entirely on who you're playing against, and the best signal for that is your actual game history.
It compounds over time
The first time you sync, you get a snapshot. Sync again next week and the data gets richer. Lines that keep appearing across multiple syncs are genuinely important to your practical play. Lines that never appear? Maybe they're worth having in your repertoire for completeness, but they shouldn't be eating your training time.
How the Matching Works
When you sync, Openings.gg parses every game from the last 30 days across both platforms. For each game, it determines which color you played and extracts the move sequence. Then it compares those moves against every line in your repertoire for that color.
A line counts as "matched" if your game followed the same moves for at least 60% of the line's length. This threshold is intentional — it catches games where your opponent played into a variation even if the game diverged at some point, but it doesn't match on just the first two moves.
For example, if you have a 20-move line in the Queen's Gambit Declined and your game followed it for 14 moves before your opponent deviated, that's a match. But a game that only matched the first 3 moves (1.d4 d5 2.c4) won't boost every QGD line in your repertoire.
How Boosted Lines Work in Training
Boosted lines don't just become due — they jump to the front of the queue. During your next training session, you'll drill all boosted lines first, before any regular due cards. Within the boosted group, lines are shuffled randomly so you're not always starting with the same one.
Once you review a boosted line, the boost clears. It goes back to normal spaced repetition scheduling. This means the boost is a one-time nudge: "hey, someone played this against you recently, make sure you know it." It doesn't permanently change the line's priority.
If you sync again later and the same line matches new games, it gets boosted again. This creates a natural feedback loop — frequently encountered lines keep getting boosted, which keeps them fresh.
Setting Up Chess.com
Chess.com setup takes about 10 seconds:
- Go to your Profile page on Openings.gg
- Find the Connected Accounts section
- Type your Chess.com username and click Connect
- Openings.gg verifies the username exists — that's all that's needed
Setting Up Lichess
If you've already connected Lichess for study imports, you're done — Game Sync uses the same connection. Your Lichess username is already stored, and your games are publicly accessible.
If you haven't connected yet:
- Go to your Profile page
- Click Connect next to Lichess
- Authorize on Lichess (this also enables study imports)
Both Platforms at Once
If you play on both Chess.com and Lichess (like a lot of players do), connect both. Game Sync fetches from both platforms in parallel and merges the results. A line in your repertoire gets boosted whether you faced it on Chess.com or Lichess — it doesn't matter where the game happened.
When to Sync
There's no automatic syncing — you click the button when you want it. A good rhythm is syncing once before your training session, especially if you've played several games since the last sync. Some players sync daily, others sync weekly. It depends on how much you play.
The sync covers the last 30 days of games, so you don't need to worry about missing games if you skip a few days. Everything in that window gets analyzed every time.
What This Doesn't Do
Game Sync is about prioritizing lines you already have, not about adding new ones. If your opponent plays the Grob (1.g4) and you don't have a line for it in your repertoire, nothing happens. Game Sync won't create lines for you — it just makes sure the lines you have get the training time they deserve.
If you notice gaps — openings your opponents play that you don't have lines for — that's a signal to add new lines to your repertoire from YouTube, Lichess studies, or PGN.
Getting Started
Connect your Chess.com or Lichess account on your profile page, sync your games, and start your next training session. The lines your opponents actually play will be waiting for you at the top of the queue.
Stop drilling theory nobody plays against you.