Question: Wikipedia's [Tsu (kana)](https://en.wikipedia.org/wiki/Tsu_%28kana%29) page says

[![tsu](https://i.stack.imgur.com/lLfL2.png)](https://i.stack.imgur.com/lLfL2.png)

> 
> つ/ツ
> 
> 
> hiragana origin 川
> 
> 
> katakana origin 川
> 
> 
> 

* How Is つ/ツ origin 川?

Answer: 
That is because the cursive script of the kanji 「川」 kind of looks like 「つ」. It should look even more like 「ツ」.

[![enter image description here](https://i.stack.imgur.com/jn3d6.jpg)](https://i.stack.imgur.com/jn3d6.jpg)  

(source: [netdna-ssl.com](https://bcpzone-tsttechnology.netdna-ssl.com/wp-content/uploads/2011/10/figure_3_4_hiragana_tsu-horz.jpg))
There are actually three candidates for the origin of つ and ツ.

One is 州, which in the [Jiankang dialect](https://en.wikipedia.org/wiki/Go-on) was pronounced "zhōu". Zhōu → tsu (origin of kana) → shuu (modern on'yomi).

The next is 川, which is generally pronounced "chuan" in Chinese. Chuan → tsuan → tsu (origin of kana) → sen (modern on'yomi).

Yet another argument is that the kana are derived from the kun'yomi of 州, which today is pronounced "su".

The way the hiragana is written might be a calligraphic form of either 州 or 川.