Start here · for absolute beginners
Where kana came from
Japanese uses three scripts at once, and every beginner is told to just accept that. You don't have to. Each one arrived for a reason, at a datable moment, and once you know the reasons the rules stop needing to be memorised — including why English words are written in katakana.
1 · The three scripts
Before any history: what the three actually are, and what each one does inside a sentence. This is the whole system in about a minute.
2 · The chronology
Nine moments, each adding exactly one piece of the modern writing system. Click a title to open it.
3 · Every kana, in Mongolian
Tap any tile to see its romaji and the character it was cut down from. Hiragana and katakana share a sound, so they share a tile — but they were carved out of different kanji, which is why they look nothing alike.
あ hiragana ア katakana а Mongolian
The eight that need a note
Most of the table is a clean swap. These are where the Mongolian letter is close but not exact — and three of them are where you start ahead of English speakers.
4 · So why are English words in katakana?
The usual answer is "that's the rule". The real answer is four steps, and once you've seen them the rule is obvious.
So katakana doesn't mean "English". It means "this word is set apart" — which is also why it takes animal and plant names in biology, onomatopoeia like ドキドキ, company names, and emphasis, the way italics work in Mongolian or English. Foreign words are the biggest group in that category, not the definition of it.
Where to go next
You now know what the three scripts are for. These tools pick up from here.