Anki vs FSRS for Chinese learners: which schedule wins?

If you use Anki with the default (SM-2), you are reviewing more than you need. Anki added FSRS as an opt-in scheduler in 23.10 — you switch it on yourself in Deck Options, a fresh install still ships with SM-2 — and Vô chi runs FSRS by default with nothing to enable. For Chinese learners, the difference is significant either way — because you have 3,000+ characters to move through, not 300.

For the mechanics of why FSRS schedules differently in the first place, see FSRS vs SM-2: what changed and why it matters — this post focuses specifically on what that means for HSK-sized vocabulary.

What SM-2 assumes

Every card behaves the same. Every learner reviews the same way. Correct → interval doubles. Wrong → back to day 1. Cheap to compute, expensive on your time.

What FSRS models

Each card has three numbers:

• Difficulty — how hard the card is for you specifically
• Stability — how many days until you would forget
• Retrievability — probability you can recall it right now

FSRS schedules the review right when retrievability drops to the target (usually 90%). Each card lives on its own schedule.

On HSK vocab, how much do you save?

The open-spaced-repetition project's published benchmarks put FSRS at roughly 20–30% fewer reviews than SM-2 for the same retention target — treat that as an order-of-magnitude figure, not a guarantee for any specific deck, since it depends on deck size and how consistently you review. The savings barely register on a 150-word HSK 1 deck. They compound once you're carrying HSK 4–6 volume: thousands of cards, many of which you've already known solidly for months, where SM-2 keeps pulling them back on a fixed multiplier instead of reading how well you actually still know them.

When the gap matters most

• Long decks (HSK 4–6)
• Learners who cannot review 7 days/week (FSRS handles gaps better)
• Working adults with 15-minute daily windows

When you might not notice

• HSK 1 alone, first 30 days — decks are short, SM-2 is fine
• If you cram in bursts and skip weeks — no algorithm survives that

Migrating

• In Anki 23.10+: it's off by default — go to Deck Options → FSRS and turn it on yourself. Optimize weights after 400+ reviews.
• In Vô chi: FSRS is the default. Nothing to configure.

Verdict

For anyone past HSK 2, FSRS beats SM-2. The gap widens as the deck grows. If you are starting HSK 4, switch today.

Try FSRS on your desktop

Vô chi is free on macOS and Windows, FSRS by default. HSK 1–3 decks ship in the app.