This is what is true of the Japanese deck in production now: 1,032 cards teaching 904 distinct words, 1.14 cards a word. It teaches at least 700 words, Flua's A1 target, reaching 700 at card 807.
Every card is checked against the rules the deck is built to each time the deck is built. The measurements below are computed here from the cards learners download, again whenever the deck is republished, and where a figure misses its rule, the page says so.
1,000 cards teach words and 32 explain grammar. A word is a dictionary form, so the forms of one verb count once: the deck teaches each form you will hear as its own card, which is why it holds more cards than words. The forms it teaches make up 71% of all words spoken in Japanese film and TV subtitles.
Some of the rules every card is built to can only be checked with the deck's full build records, so they run on every card each time the deck is built, before it can be published: one new thing per card (every word of every sentence taught by an earlier card letter for letter, the card's own new word, or a regular variant of a word taught earlier, such as a plural or an elided article, shown after the card that explains its pattern), every meaning of a word taught before it is used, words taught in the order people use them, explanations that use only words already taught, and complete audio on every card. Their card-by-card results aren't published with the deck, so this page doesn't restate them; everything below is measured here, from the cards learners download.
Coverage is the share of all words spoken in Japanese film and TV subtitles that are exactly a form the deck has taught by that card. It is 51% after 100 cards, 61% after 300 cards, and 66% after 500 cards. Common words come first, so the curve rises fast and then flattens.
Characters per sentence across all 1,032 cards, punctuation and spaces left out. Mean 10.9, median 11, longest 23. Japanese is measured in characters because splitting it into words takes the same analyzer the deck is built with, which this page doesn't run; the deck's 10-word limit is checked when the deck is built, not here.
By position, in steps of 50 cards. The deck is built to start short and grow, with its first 100 sentences the shortest; in this deck cards 1–50 average 5.6 characters and cards 1,001–1,032 average 12.2.
Each taught form must be heard again on at least one later card, in a new sentence. 881 forms are held to that rule and all of them return. The last 30 vocabulary cards are exempt, because no later cards are left to bring them back without breaking the one-new-thing rule. The bars and the median cover those 881 forms only, not the exempt ones. A form is heard 2 times in the median; 75% of the required returns come more than 30 cards after the form is taught, spaced rather than straight after, and 93% come back within 200 cards. No form is the new word of two cards in the same meaning, and every new form appears in its own card's sentence. Repeating a word on a schedule is the review system's job; the deck's job is a second voice and context. Which voice reads each card isn't part of the published deck, so voice variety isn't measured here.
32 grammar cards explain patterns, the first at card 88, with a median of 13 cards between one and the next. The rule: never two in a row, and at most 5 in any 20 cards. No grammar card follows another directly, and the busiest 20 cards hold 5.
1,032 of 1,032 cards have audio (1,032 files in all) and 1,032 have a picture. Two cards with the same sentence would be the same card twice, so sentences that differ only in capitals, accents or punctuation count as one: no sentence appears on two cards.
Measured 2026-10-29 09:54 UTC.