How the scheduling works 復習
FSRS, and where it actually runs. What a card's level means, and why the schedule is not the browser's to decide.
A review asks one thing and grades it. What happens next, when you see that card again, is the whole of what a spaced repetition system does, and it is the part worth understanding before you trust one with a year of your attention.
FSRS, not a fixed ladder
EdoQuest schedules with FSRS - the Free Spaced Repetition Scheduler. Rather than moving a card along a fixed ladder of intervals, it keeps two numbers per card: how stable your memory of it is, and how hard you personally find it. Every answer updates both, and the next interval falls out of them.
The practical difference is that the schedule adapts to you per card. A character you find obvious pulls away quickly; one you keep missing stays close, and keeps staying close until it stops being missed. You do not tune anything - answering honestly is the input.
Where it runs, and why that matters
The browser never computes a schedule. It submits a log of what happened (which card, what you answered, when, and how long you took), and the server replays that log through FSRS to decide the next due date.
That is a deliberate choice rather than an implementation detail. A schedule computed in the page is a schedule the page can be persuaded to lie about, and a year of study is worth exactly as much as its record is trustworthy. Keeping the arithmetic on the server means your history is a record of what you actually knew.
What a card's level means
A card's level is a plain-language band over how stable it has become. The boundaries are how long the card would hold:
- level 1 - 8 hours
- level 2 - 1 day
- level 3 - 3 days
- level 4 - 1 week
- level 5 - 2 weeks
- level 6 - 1 month
- level 7 - 3 months
- level 8 - 6 months
- level 9 - 1 year
Below level one is level zero: under eight hours, which is to say not yet held at all.
Level seven is マスター mastered - the card would still be there in three months. That is the point at which it counts in full toward your rank, and it is a deliberately high bar: a card answered right once is not learned, and a system that treats it as learned is flattering you.
Two levels sit above it, at six months and a year 完成 complete, because a thing you have truly kept deserves to be visibly different from a thing you have merely passed.
One thing the levels are not: a timetable. Those durations say what the level means, not when the card is next coming. FSRS works out each due date from that item's own history, so two travelers sitting on the same level can have quite different next reviews - which is the entire reason for using it.
Two tries when you type, and what counts as easy
When you write the answer you get two tries. Sometimes you read on'yomi where kun'yomi was asked, sometimes you mistype, and sometimes your hands answer before you do. A single slip is not evidence that you have forgotten something, and treating it as such would poison the schedule.
A tapped かるた card is the one answer you get. Choosing again from the three cards left over is a coin flip rather than a recall, so there is nothing there worth telling the schedule.
Cards you do miss come back at the end of the same session, so a session ends with the things you found hard rather than the things you found easy.
Speed counts in exactly one narrow way. A first-try correct answer under two and a half seconds is recorded as easy rather than good, which lets the interval grow faster. A tapped card is never recorded as easy at all - recognising the right answer among four is not the same as knowing it, and the schedule should not pretend otherwise.
Typing, or tapping
You can write the answer or tap one of four かるた cards. Both are free, and the reason both exist is that typing Japanese on a phone is its own separate skill. A learner who knows a character perfectly well can still fail the card because the input method fought them, and that failure teaches nothing and corrupts the schedule.
The four cards are not padding. A wrong option has to be something the grader would not have accepted, not a repeat of another option once normalised, and drawn from the same kind of answer nearby in the corpus - so the wrong cards are the ones you might genuinely confuse, and getting it right means something.
When you do type, romaji becomes kana as you go on reading questions - ka gives か, kya gives きゃ, and a doubled consonant like kko gives っこ. You do not need a Japanese keyboard installed.