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Reference databases and wizard defaults
LPDO complements your own games with a shared reference database — a large, regularly-updated collection used for opponent preparation and opening/move statistics. The setup wizard picks sensible defaults so you don't have to compare sources yourself. This page explains what those defaults are and why.
- No reference database — just your own games.
-
Free, kept up to date (recommended) — a public-domain historical base plus
live updates, with the optimal date split applied automatically:
- Ajedrez (public-domain over-the-board history) for games up to 2012,
- The Week in Chess (TWIC) for 2013 onward (~99% FIDE-identified),
- Lichess Broadcasts as a complement (adds broadcast events TWIC doesn't carry).
- Bring your own (e.g. ChessBase Megabase) — import a database you own as the historical base, plus the live updates. Best coverage if you have it.
You can change any of this later in Maintenance → Sources.
The property that matters most is whether games are reliably linked to FIDE player IDs — that's what lets statistics and preparation find all of a player's games across sources, even when names are spelled differently. Measured coverage:
| source | role | FIDE-identified |
|---|---|---|
| TWIC | live updates (2013+) | ~99% |
| Lichess Broadcasts | live complement | ~90% (recent years) |
| Megabase (bring-your-own) | historical base | ~95% (modern) |
| Ajedrez (free base) | deep history | ~0% natively |
Ajedrez is the only free, cleanly-licensed source deep enough to serve as the historical base — but it carries no FIDE IDs and its most recent years are noisy (abbreviated names), whereas TWIC covers 2013 onward at ~99% FIDE with clean names. So the optimal setup is Ajedrez for the deep history (≤ 2012) and TWIC + Lichess for the modern era (2013 +). For the free base, LPDO fills in FIDE IDs by matching player names against a shared lookup, which already resolves most of Ajedrez's pre-2013 players.
If you own Megabase, it's a stronger historical base (real FIDE IDs throughout), so the "bring your own" option needs no name-matching step.
Why both TWIC and Lichess? They mostly don't overlap — only about a third of Lichess broadcast games are already in TWIC, so Lichess adds a large set of events (including club/junior tournaments) that TWIC doesn't compile. TWIC is the higher-quality core; Lichess broadens the coverage.
The "kept up to date" default brings in roughly (as of mid‑2026):
| updates | new games / month |
|---|---|
| TWIC only | ~28,500 |
| Lichess Broadcasts only | ~29,400 |
| TWIC + Lichess (recommended) | ~49,400 |
The combined figure isn't the sum — TWIC and Lichess share about 8,600 games a month, so after de-duplication Lichess adds roughly +20,900 unique games/month on top of TWIC. The exact number varies with the tournament calendar (busier in summer and year-end).
The complete analysis — measurements, per-year coverage tables, and licensing — is in the issues: