Junka (a diving method) (順下)
Junka is a diving method of Japanese martial arts swimming.
Summary
A diver takes off with one leg from a height and opens both legs like a running stride at the point of diving. Immediately after hitting the water, he strongly closes both legs and pushes the water down with both hands, to avoid the head sinking under water.
This is said to be a measure to be able to gaze steadily at the enemy even when a person dives wearing Kacchu (armor and helmet).
It is also said to be the specialty of Mukai school.
It is also adopted in Ota group of the Suifu school (a style developed for swimming and combat in fast steams).
It is called 'jingasa tobi' (literally, "soldier cap jumping") in Kankai school. It is reportedly named as this method is used when wearing jingasa (a soldier's cap).