An active training system

Train your own lines.

Not a course shop. Not a tactics drill. Your repertoire - imported from PGN or Lichess study - turned into measurable recall under engine pressure.

Start free → See how it works ↓

Imports from

Lichess studies · PGN files · Chess.com (soon)

The problem

01

You studied the line. You'll forget it.

Memory decays past 14 days on lines you don't drill. Most opening tools ship you more content - courses, videos, books - and assume the retention will sort itself out. It doesn't. OpeningOS measures what you actually still know and serves you the next position you're about to lose.

How it works

02

One loop. Three moves.

  1. 01

    Import

    PGN file, paste, or Lichess study (public or private). Each game becomes a variant. Your tree, untouched.

  2. 02

    Drill

    Revision walks you through. Sub-lines on your side stay for context (not as challenges) - only the prep main move counts.

  3. 03

    Practice your repertoire

    Blitz hands the position to Stockfish 18 the moment your prep ends. It punishes drift the way a real opponent will.

Modes

03

4 training modes.

Library

04

Private by default. Shared on your terms.

Every repertoire is yours alone unless you decide otherwise. Share a line by public link - no login required to view it. Browse community repertoires in Discover and fork the ones you want into your own training.

Open Discover →

Pressure Recall

05

The score that holds up under pressure.

Pressure Recall combines accuracy, recency, and stability - and it decays when you stop, strengthens when you return. No streak gamification, no points to grind - the honest signal of what you'd still play correctly tomorrow.

What you'll see

06

Weakest positions, surfaced every visit.

The positions you keep missing rise to the top of the dashboard - with the correct move drawn as a green arrow on each. One click and you're drilling them.

OpeningOS dashboard - weakest positions with the correct-move arrow drawn on each
Fig. 1 — The dashboard, weakest positions first.

Pricing

07

Two plans. Both serious.

No course shop, no upsell. The free tier covers a real evaluation; the paid tier covers a real player.

Free

0 € forever

One repertoire. Revision only. Enough to feel the loop and decide.

  • — 1 repertoire
  • — Revision mode
  • — Per-move feedback
  • — Lichess study import (public)
Start free →

Pro

15 € / month

120 € / year - save 33%

Unlimited repertoires, every mode, engine play-out, full analytics. The whole tool.

  • — Unlimited repertoires
  • — All training modes (Revision · Blitz · Tournament · Random)
  • — Engine play-out (Stockfish 18 local)
  • — Full analytics + readiness score
  • — Lichess private studies
  • — Sibling-line hints + cited-game detection
Start 14-day trial →

For titled players

FM, IM, GM - and WFM, WIM, WGM - get Pro for free, for life.

Submit your FIDE ID, we verify, the entitlement is permanent.

Verify my title →

FAQ

08

Common questions.

Is OpeningOS an opening course?
No. We do not sell content. You bring your own repertoire.
How does the Lichess import work?
Connect via OAuth, pick the study you want, and OpeningOS imports it. Private studies are supported.
Can I cancel anytime?
Yes. Your data stays yours, export as PGN any time.
Are my repertoires private?
Yes. Your repertoires are fully private - only you can see them.

Stop studying. Start retaining.

Create your account →