Kakera

Kakera (欠片, "fragment") is a flashcard app for the words that will not stick. Each card is one small piece of a language; reviewed at the right moments, the pieces add up to a whole.

REVIEW A WORD JUST BEFORE YOU WOULD FORGET IT
Every word keeps three numbers: how stable it is in your memory, how hard it is for you, and how likely you are to recall it today. Kakera schedules with FSRS-6, the open spaced-repetition model, and brings a word back when that chance falls to 90%. Each review you pass makes the gaps grow, from days to weeks. Each rating button tells you when the word will come back before you tap it.

A CARD THAT EXPLAINS THE WORD, NOT JUST TRANSLATES IT
Paste a list of words and Kakera writes a card for each one: the meaning in Chinese and in English, examples, where the word comes from, its parts, the words it is confused with, and the phrases it lives in. It runs on your own Claude or OpenAI API key, kept in the iPhone's Keychain. Pick any model your key can use.

JAPANESE, WITH THE READINGS ON TOP
Switch the deck to Japanese and every sentence carries furigana. Cards give the kana reading with its pitch accent, split the word into morae, and take the kanji apart. In a quiz, hiragana and katakana count as the same answer. English and Japanese keep separate decks; hide the readings once you no longer need them.

AND THE REST
• Pronunciation for every word, played as the card turns
• Quizzes after each session that feed the same schedule
• A daily story made of the words you just reviewed
• Stats: the forgetting curve, memory maturity, what will slip this week, and your streak
• Search, tags and notes of your own
• A home-screen widget and a daily reminder at the hour you pick
• Light and dark appearance

YOUR WORDS STAY YOURS
No account, nothing to sign up for. Kakera has no server of its own: your deck lives on your iPhone and syncs between your devices through your own private iCloud database. Your AI key goes only to the provider you chose, and only when a card is written.