Kanji.koohii Explained: Crowd-Sourced Stories and an SRS for Heisig Learners
Kanji.koohii is a free, community-driven web application built around James W. Heisig's Remembering the Kanji (RTK). It pairs a story bank of crowd-sourced mnemonics with a built-in spaced repetition system and a kanji-aware dictionary.1 For learners working through RTK volume I, it answers the method's hardest question: where to find a story that locks in a keyword when invention runs dry.2
Overview
What kanji.koohii is, in one line
The site bills itself as "A web application designed to help Japanese language learners remember the kanji." Its landing page names three deliverables: kanji mnemonics, flashcards with a "friendly spaced repetition system" that schedules reviews "at increasing intervals to stimulate long term memory," and a "smart dictionary" that "highlights words which uses only the kanji that you have learned."13
The story bank covers the 2,200 kanji of RTK 6th edition, with each character's Study page surfacing the three top-voted community stories alongside two random unvoted ones.4
"Koohii" is the romanized Japanese reading of コーヒー (kōhī), the standard word for "coffee."5 The URL is meant to be read as "kanji coffee," not as a technical term.
Who it is for
The primary audience is learners actively working through Remembering the Kanji. The site's keyword-to-character review direction, asterisk-marked primitives, and brace-syntax cross-references all encode RTK conventions, so the workflow only pays off for readers who accept the Heisig method as their kanji track.62
Heisig's "imaginative memory" approach asks the learner to invent or borrow a story for each of 2,200 characters. Each story binds an English keyword to a set of primitives that make up the written form.27 A shared bank fills the gap the book leaves once the author stops modelling stories and hands the rest of the volume back to the reader.2
What it is not
RTK volume I "focuses on writing and meaning only"; on'yomi readings are deferred to volume II.28 Kanji.koohii inherits that scope and is therefore not a reading-acquisition tool.
It is also not a vocabulary SRS. The smart dictionary surfaces words built only from kanji the learner has flashcarded, but it does not schedule those words for review.6 And it is not a beginner front door for Japanese: the entire workflow assumes the learner is following RTK's keyword sequence and is willing to read or write mnemonic stories.6
The story bank: crowd-sourced mnemonics for every RTK kanji
How a story is structured
A story on kanji.koohii is a short scene that ties the Heisig keyword to the meanings of the primitives that make up the character. The platform uses typographic conventions to make the structure scannable. Keywords are highlighted automatically when the story text matches them, and a writer using a non-standard spelling can force-highlight a phrase by wrapping it with hash marks, as in #like this#.6
Primitives are italicised by enclosing them with star characters, as in *like this*.6 Cross-references to other kanji use brace syntax. The writer can link to another character by either its Heisig frame number or the kanji itself, as in {113} or {山}.6
Each kanji's Study page shows three top-voted stories first, then two random unvoted stories below them, giving newcomers exposure to both the consensus mnemonics and the long tail.4
The site's own database documentation notes that "Framenumbers are no longer supported because they change between editions and potentially even additional sequences." UTF-8 kanji characters are the durable URL key instead.4
How upvoting and stars surface the best-rated stories
The story list on each Study page is sorted by community votes, so the highest-rated mnemonics rise to the top.4 This is the "best-rated stories" mechanic the Heisig ecosystem leans on. A learner stuck on a primitive can read what worked for hundreds of other readers without having to write their own story first.
A second mechanic, the star, picks which single story follows the learner into review. The "Learn more" reference states the rule directly: "If you don't edit a story, the first one that you star will be shown during flashcard reviews when you use the Story shortcut."6 The star is per-learner, so two readers can flashcard the same kanji and see different prompts.
The diagram above traces the new-kanji loop end to end and is referenced again in the workflow section below.
Why a shared bank works for Heisig specifically
Heisig's volume I models stories for the early chapters and then steps back, leaving most of the 2,200 characters to the learner's own invention.2 In practice, many readers stall on the harder primitives mid-book. A thirty-second skim of three or four community stories often delivers the one image that locks in.
Kanji.koohii's database is keyed to the full RTK 6th-edition character set, so the bank is dense exactly where the book's hand-holding thins out.4
Copyright rule that shapes the bank
The site's About page states that user-contributed stories on Study pages are "licensed under Creative Commons BY-NC-SA," and that frame numbers and keywords are sourced "from James W. Heisig's works."5 The community-stories licence is what lets third-party Anki decks redistribute the highest-voted stories with attribution.59
Content rules forbid reproducing Heisig's published stories verbatim, and the site exposes a report mechanism to flag uploads that copy the book.5 The first time a new learner sees this rule it explains why "the book's story" is never on a kanji's page.
How the built-in SRS works
The colour-coded Leitner model
The on-site flashcard system is a Leitner-style box model, visualised as stacks of cards progressing left to right.6 Instead of numbered boxes, the interface uses four colours that describe the state of each stack.
| Colour | Stack | What it holds |
|---|---|---|
| Red | First box, failed pile | Cards "which have not been answered correctly"6 |
| Blue | First box, untested pile | Cards "that have not been tested yet"6 |
| Orange | Later boxes, due pile | Cards "ready for review and need your attention"6 |
| Green | Later boxes, scheduled pile | Cards "scheduled for review, but have not expired yet"6 |
Correct answers move a card rightward into a longer-interval box. A failed answer drops it back to the red pile in the first box.6 The mechanic descends from Sebastian Leitner's 1972 So lernt man Lernen, which introduced the box system that later flashcard schedulers build on.1011
The state diagram traces a single card through the four colours over its life. The shape is the core of the SRS. It earns a picture because the rules can read in plain prose as a tangle of "if Yes then promote, if No then demote."
The review direction: keyword to character
The "Learn more" reference is unambiguous: "Reviewing is done from the keyword to the character, and not the other way around."6 The card shows an English keyword such as "mountain"; the learner is expected to reproduce the kanji from memory.
山7
"mountain"
This direction matches RTK volume I's design. It trains production of the character from its keyword and primitive composition rather than recognition of an unfamiliar form.72 Recognition-only SRSes invert the prompt and train a different skill.
Heisig's pedagogy treats writing the character on paper, or tracing it on a palm, as part of each review: the production step is what binds the story to motor memory.7 Kanji.koohii's review screen does not formally require this, but the keyword-to-character direction only pays off if the learner actually produces the form before checking the answer.6
Rating options on each card
The built-in SRS exposes five answers and no other knobs. The "Learn more" reference documents each one:6
- No sends the card back to the restudy pile.
- Again moves the card to the end of the review pile and lets the learner repeat it in the same session.
- Hard demotes the card to a lower pile, with the next review scheduled at a shorter interval.
- Yes promotes the card to the next box, scheduled at a longer interval.
- Easy promotes the card and lengthens the interval by 50 % beyond what Yes would have given.
This is the entire control surface. Some learners outgrow it after a few hundred kanji, which sets up the Anki hand-off discussed below.
The smart dictionary tied to your progress
The dictionary helps close the loop between meaning-only RTK and real Japanese vocabulary. The "Learn more" reference states the rule: "Koohii dictionary is aware of your kanji knowledge: as you progress and add flashcards the dictionary will highlight vocabulary entries that are made of only those known kanji."6
The site defines known narrowly: "Currently known kanji means a kanji for which the user added a flashcard."6 As the flashcard count grows, more vocabulary entries qualify as fully readable.
The data behind the dictionary is "Jim Breen's JMdict/EDICT Japanese-English dictionary," restricted to its priority entries, which number "approx. 16000 of the most common words."612 This is the closest thing kanji.koohii has to a bridge from meaning-only RTK into vocabulary. It is a visualisation aid rather than a vocabulary trainer.
How to actually use the site, end to end
The new-kanji loop
A working daily session pairs the book with the site step by step.
- Read the relevant RTK volume I lesson in the book.7
- Search the kanji on koohii by keyword, character, or Heisig frame number. The Study Search box accepts all three.613
- Read the three top-voted stories on that kanji's Study page, and optionally the two unvoted stories below them.4
- Write a story, or copy and edit a community one.6
- Star the story to be shown during reviews. The first starred story is the one the Story shortcut surfaces.6
- Add the flashcard. The card lands in the blue untested pile of the first SRS box.6
This is the same flow the flowchart above traces. Mid-book learners often skip steps 3 and 4 when a kanji's top-voted story is obviously strong. They then spend more time on harder primitives.
The review loop
A review session works the orange due-card pile first. The learner reads each keyword prompt, produces the character, flips the card, and rates the answer with one of the five options.6
Promotion to a longer-interval box happens on Yes or Easy. Demotion happens on No or Hard. Again re-queues the card inside the current session.6 Once the due queue is clear, the site filters new cards in from the blue untested pile and lets the learner work them.6
The platform does not enforce a daily new-card cap, leaving cadence to the learner.6 In practice RTK pace math sits somewhere between a dozen and a few dozen new kanji a day, depending on how much study time the learner has.
Searching the bank: by keyword, character, or Heisig number
The Study Search box supports three lookup paths to the same destination: keyword search, kanji-character search, and Heisig frame number lookup.613 New users tend to default to keyword search because that is the entry point they already know from the book. Mid-book learners often switch to frame-number lookup once they are working linearly through a lesson.
A site update added support for custom keywords in the search box, so user-created keywords are indexed alongside standard Heisig entries.13
Reading mode and progress tracking
The site tracks which kanji a learner has marked as studied by adding flashcards. The dictionary uses that set to highlight vocabulary built only from those kanji.6 The SRS chart on the review page visualises stacks of flashcards moving rightward into longer-interval boxes. A Review Summary breaks each session down into per-rating counts sortable by column.6
The highlighting view is a milestone tool that confirms progress, not a substitute for sustained reading practice on real Japanese text.
Limits, status, and the Anki hand-off
The forum closed in 2019; the site itself is still developed
The structural change the primary sources document is the closure of the Koohii Forums in 2019, not a halt on the site. The closure was announced on March 2, 2019 ("I've recently made the decision to close the Koohii Forums"). A follow-up post in late May 2019 confirmed that "the forum is now permanently closed."1415
Founder Fabrice Denis paired the closure with a clear statement on the site itself: "I'm still running Kanji Koohii and have no intentions to end this service anytime soon."14 The blog has continued to ship feature work since, including "Custom keywords support in the search box" and "Flashcard layout improvements."13
The "maintenance mode" framing in the wild traces to the Koohii2Anki repository's README. It describes the site as "depends on a man and a few contributors," with development "stalled" and in "maintenance mode."16 That characterisation predates the site's feature activity, and the durable structural change is the forum closure rather than any halt on the site.13
Online-only, with the connectivity tax that implies
The site documents flashcard support for desktop and mobile but does not advertise an offline mode.3 All review state lives server-side, including SRS box positions and the per-card starred story.6 A learner on flaky internet, or on a commute without service, loses review days. That is the single most commonly cited reason readers migrate to Anki midway through volume I.17
When learners graduate to Anki
The canonical hybrid pattern is "stories from koohii, reviews in Anki," and two artifacts document it. The AnkiWeb deck "Heisig's Remember the Kanji 1-3 w/top 2 community stories" bundles the two highest-voted koohii stories per kanji into an Anki schedule. It is one of the most widely downloaded RTK decks.9 The Koohii2Anki repository ships a migration path that exports a learner's own koohii stories and progress into Anki via a CSV export and a getstories script, with optional add-ons for stroke order and review history.16
Both tools treat the koohii story bank as the durable source of truth for mnemonics, even when the SRS scheduling moves to Anki.169 The story bank's CC BY-NC-SA licence permits that redistribution.5
What is not here
The scope is narrow on purpose. RTK volume I, which the site is built around, explicitly defers on'yomi to volume II,28 so there is no readings track beyond what the dictionary surfaces by accident. There is no vocabulary SRS, only the kanji-aware highlight on JMdict entries.6 There is no grammar coverage and no audio for kanji or words. The site does the RTK-style "meaning plus writing" pipeline and stops.62
Good to know
"Koohii" is the Japanese reading for "coffee"
The site's own About page frames the name as "a playful domain name that Japanese learners typically read as コーヒー (coffee), making the site's URL readable as 'kanji coffee.'"5 The katakana form コーヒー is the standard modern Japanese word for the drink. The URL play is most useful as a memory hook for the address.
Add the flashcard, but star a story first
The single most common new-user mistake is adding a flashcard without first starring a story. The card enters the SRS, but the Story shortcut shows nothing on review, which defeats the point of the bank. The rule is explicit in the site's reference: "If you don't edit a story, the first one that you star will be shown during flashcard reviews when you use the Story shortcut."6
The correct order is to read the top-voted stories on the Study page, star the one that resonates, and then add the flashcard. Re-starring later replaces the prompt without disturbing the SRS position, whether a better story shows up or the learner writes their own.
"RevTK" is the old brand name
The site was originally called "Reviewing the Kanji" (RevTK). The 2010 open-sourcing announcement carried the title "Reviewing the Kanji goes Open Source!", and the rename to "Kanji Koohii" was announced on March 6, 2015.1819
Older blog posts, the wiki at rtkwiki.koohii.com, and many archived forum threads still use the RevTK name. As a result, search results split between the two brands without flagging that they refer to the same product.18
Story coverage falls off past RTK volume I
The community story density is concentrated on RTK volume I keywords. The sample database is keyed to "2200 RTK kanji (6th edition)." The site's frame-number model was deprecated specifically because of edition drift across the Heisig volumes.4 Volume III's additional 800 kanji exist in the underlying kanji set, but the per-kanji story density is not comparable to volume I.20
A learner planning a full volume I-to-III run should expect to write more of their own stories from the volume-III material, and budget study time accordingly.
Free with optional support
The landing page is explicit: "It's free!"3 All features, including the story bank, the SRS, and the smart dictionary, are accessible without payment. There is no paid tier blocking core functionality.36 Voluntary supporter contributions help cover hosting costs but do not unlock features.
Heisig edition drift in keywords
RTK volume I has been published in multiple editions, with the 6th edition appearing in 2011. The koohii database tracks the 6th-edition keyword list.74 A learner studying from an older copy or an imported-translation edition will hit the occasional keyword mismatch.
The fix is to anchor on the koohii keyword when adding a flashcard, because the site's search and review prompts use the 6th-edition form. Volume II and volume III have their own publication histories, with the most recent revisions of both appearing in 2012.820
User stories are CC BY-NC-SA, not public domain
The About page states that "All user-contributed stories on our Study pages are licensed under Creative Commons BY-NC-SA."5 The licence permits redistribution with attribution and non-commercial use, which is what makes third-party artifacts like the AnkiWeb "top 2 community stories" deck legal.59 It also means that any tool or article republishing a koohii story owes attribution to the original author.
See also
- WaniKani Explained: How the Radical, Kanji, and Vocabulary SRS System Actually Works
- Learning Kanji Through Vocabulary: The Kanji-in-Context Approach
- Beyond Anki: SRS Tools and Approaches Compared
- Choosing Your First Japanese Resources: Free vs. Paid
- How to Learn Japanese: The Complete Roadmap from Zero to Fluency