Mizukiri (水切り)


Mizukiri is a game of throwing a stone with spin toward the water surface to make it skip over the water. Mizukiri in this sense will be discussed in detail in this section later.

Mizukiri is the most typical way of water raising. It is one of the methods used in Japanese flower arrangement and the businesses dealing with real flowers for keeping cut flowers fresh. It is practiced by soaking the stems or roots of plants and cutting them in the water.

Mizukiri is not to spray water before harvesting farm products. This gives a high sugar content. It is practiced to grow fruits such as melons.

Mizukiri is to drain off water drops and moisture from foodstuffs or objects. It also means a kind of bowl (a cooking utensil) which is used on this occasion: colander.

Mizukiri is one of the construction methods which is used to prevent rainwater from leaking into cracks of a building or a foundation.

Mizukiri is cargo work in which cargo are unloaded from a freight vessel.

Mizukiri is a game of throwing a stone with spin toward the water surface to make it skip over the water, sometimes competing how many times the stone skips.
It is also called 'Mizu no ishikiri' or 'Ishikiri.'
This is the kind of game which can be seen anywhere in the world, as long as the water surface above a certain size and stones are available. The game is called "Stone skipping" in the United States.
The unit of the number of skipping in Japan is 'dan.'

As a game easy for everyone, mizukiri is played everywhere and mizukiri events are also held. There are the citizens' club-like organizations in Kumagaya City and so on.

To play mizukiri, it is necessary to make sure that there is no one swimming in a forward direction in order not to hurt people nearby, and also to be considerate of wild animals such as waterfowls.


As of 2008, listed in Guinness World Records is 51 skips made by Russell Byars on July 19, 2007.

Until then, the record was 40 skips made by Kurt Steiner at "Pennsylvania Qualifying Stone Skipping Tournament" on September 14, 2002.

Japan's record was set with 32 skips by Shunsuke Watanabe, a pitcher of the Chiba Lotte Marines, in a TV program, 'Tokumitsu Tokoro no sports eraihito Grand Prix' (Tokumitsu and Tokoro's Great-People Grand Prix of Sports).

Other names

The game is called by various names other than 'Mizukiri' and 'Ishikiri.'

Ishinage (Stone-throwing)
Haneishi asobi (Skipping-stone game)
Suimen ishitobashi (Stone-throwing over water surface)

Scientific investigation
Necchu jikan bochu "shumi" ari' (The enthusiasm time, Enjoy a hobby even if you are busy), a TV program on NHK, introduced the scientific analysis of mizukiri using an ultrahigh-speed camera and a computer. According to the analysis, the optimum angle for skipping stones is for the front face to be raised by 10 degrees with respect to the surface of the water. It is important that the stone is rapidly spinning (at 30 revolutions per second in the program) because if the revolution is slow it falls into the water quickly. Ideal shapes of the stone are flat, semicylindrical, lenticular and so on, but according to calculations, the best shape is lenticular.

According to the research by French physicist Lydéric Bocquet, Shinichiro NAGAHIRO (presently at Sendai National College of Technology) and so on, for the best bounce of the stone, the optimum angle between the stone and the water surface is 20 degrees. Bocquet has calculated that it requires a speed of 12 m/s and spinning at 14 revolutions per second to achieve 38 skips, the former Guinness world record set by Coleman-McGhee.

Bouncing bomb

Bouncing bomb was made by applying the theory of Mizukiri to a weapon. The one which was developed by the United Kingdom during World War II in order to destroy a dam in the Ruhr area of Germany is well-known by the name of "The Dambusters." Please refer to "Operation Chastise."

[Original Japanese]