Doi Toshitsura, the 4th daimyō of Koga Domain started observing snowflakes as his hobby with his own microscope which was imported from the Netherlands, and he drew pictures and studies about snowflakes in a book (Sekka Zusetu). This figure collection of his is highly valued today in Japan as the first Japanese figure collection of snowflakes.
It's said that Toshitsura had many difficulties to observe snowflake properly because snowflakes need −10 to −15 Celsius degrees temperature to hold their correct shapes. So Toshitsura had to observe them under very cold temperatures.
This book was written for him and his family (Doi clan, 土井氏), but it had great influence on Japanese textile-patterns also. As soon as he wrote the book, snowflake patterns (雪華模様) became popular among ordinary people in Edo.
This figure collection is now available on the internet ().
How Toshitsura observed
- Put a black cloth outside at night when it seems cold enough to snow.
- Receive snowflake with the cloth (see 1).
- If you get snowflakes, pick them up carefully and put into a black cup.
- Be careful not to breathe on them, and observe them with a microscope.