Caterpillars become butterflies

"Caterpillars become butterflies" is the name of the third and final micro season of the third solar term of the year, which is known as "Keichitsu", "Insects Awaken."  Overall, "caterpillars become butterflies" is the 9th micro season of the year. 

In Japanese Caterpillars become butterflies is called Namushi chō to naru 菜虫化蝶. In 2026, this micro season started on March 15th and ends on March 19th. It is a period when the natural world is warming enough for overwintering caterpillars and pupae to complete their metamorphosis. 

During this period you can usually see the first butterflies of spring, often the cabbage white butterfly (Pieris rapae), which is usually one of the first species to appear. In addition, there is a softening of the landscape and more of a transformation from winter to spring.