Mizugumo

Mizugumo (Japanese: 水蜘蛛, lit.

'water spider') was a water crossing device used by ninja.

a device was worn like a harness around the hips and had small air pockets to keep the ninja afloat.

[better source needed] In an episode of MythBusters, another mizugumo made of wood and rope which was attached to the feet was tested.

This was deemed to be 'busted' for walking on water, though possibly effective for rice paddies or marshy areas.