シ vs ツ and ソ vs ン: How to Tell Similar Katakana Apart
Every katakana learner hits this wall: シ (shi) and ツ (tsu) look nearly identical, and so do ソ (so) and ン (n). Squinting doesn’t help, fonts make it worse, and getting one wrong changes the word — シール is “seal (sticker),” ツール is “tool.”
The good news: the difference isn’t arbitrary. It comes down to one consistent rule about stroke direction, and it’s backed by real history that makes it stick. Five minutes here, a bit of the right practice after, and this stops being a problem forever.
The rule: horizontal family vs vertical family
The four characters split into two families:
- シ (shi) and ン (n) are the horizontal pair. Their short strokes stack vertically on the left, lie relatively flat, and the long final stroke is drawn from the bottom, sweeping up to the right.
- ツ (tsu) and ソ (so) are the vertical pair. Their short strokes line up across the top, standing relatively upright, and the long final stroke is drawn from the top, sweeping down to the left.
That’s the whole rule. Up-sweep from below: シ and ン. Down-sweep from above: ツ and ソ. Within each family, the only remaining difference is the number of short strokes — シ has two dots, ン has one; ツ has two, ソ has one.
| Character | Reading | Short strokes | Long stroke |
|---|---|---|---|
| シ | shi | two, stacked on the left | sweeps up from bottom |
| ン | n | one, on the left | sweeps up from bottom |
| ツ | tsu | two, across the top | sweeps down from top |
| ソ | so | one, at the top | sweeps down from top |
This is why the pairs are impossible to distinguish as static pictures but easy to distinguish as movements. The shape is ambiguous; the writing motion never is.
The history that locks it in
These four aren’t randomly similar — each katakana was cut from a parent kanji, and the parents explain the directions:
- シ comes from 之, a classical character whose meaning relates to a winding path — its strokes lie down and flow across, like water. Horizontal energy.
- ツ comes from 川, the kanji for river — three strokes standing tall, like a river’s current seen from above. Vertical energy.
- ソ is the top two strokes of 曽 — clipped from the top of its parent, pointing down.
- ン keeps the opening strokes of 尓 — a dot, then a sweep climbing upward.
“シ flows flat like a winding stream, ツ stands tall like a river” is the kind of hook that survives months of not practicing — because it isn’t a made-up cartoon, it’s where the characters actually came from. KanaLearn surfaces these origin stories right on each character’s introduction card, precisely because the look-alike set is where history earns its keep. (More kana ancestry in our origins guide.)
Reading tricks for the wild
When you meet these in real words and can’t replay stroke order in your head:
- Position is a huge hint for ン. The syllable n ends words and syllables constantly (ラーメン, パン); so rarely does. A one-dot character at the end of a loanword is almost always ン.
- ツ is everywhere in doubled consonants. A small ッ marks doubled consonants (カップ, kappu) — small size plus top-row dots means tsu.
- Check the tilt. Even in flat fonts, シ/ン’s dots sit lower and lean flatter; ツ/ソ’s dots hang from the top line.
How to make it permanent: confusion training
Here’s the counterintuitive part. Studying シ on Monday and ツ on Thursday, each in its own comfortable context, lets you be “right” without ever resolving the confusion. What actually fixes look-alikes is being forced to discriminate — seeing the confusable characters side by side, as each other’s answer options, repeatedly, until the difference is perceptual rather than reasoned.
This is exactly how KanaLearn handles it. Once you’ve learned the members of a confusable set, the app quizzes them against each other: look-alike characters appear as each other’s distractors in review, and a dedicated look-alike round mixes both scripts and both directions (character → sound and sound → character) across every confusable group — not just シ/ツ/ソ/ン but ハ/ヘ, う/ら, ね/れ/わ and the rest. Combined with animated stroke-order playback (watch シ sweep up and ツ sweep down, rather than reading about it) and finger tracing, the distinction moves into your hands and eyes, where it belongs.
The bottom line
- Direction is the rule: シ and ン sweep up; ツ and ソ sweep down.
- Dots: two for シ/ツ, one for ン/ソ.
- The kanji origins (之 flows, 川 stands) make the rule memorable.
- Side-by-side discrimination practice — not separate study — makes it permanent.
A week of mixed practice and you’ll wonder how these ever looked alike.