These are a special form of geta, with a single, centered "tooth", traditionally called tengu-geta (or ippon-ba - one tooth).
According to Japanese popular beliefs, the Tengu (long nosed goblin - supernatural beings living on this sacred mountain) prefer wearing these very tall geta.
It seems that a Tengu lost his geta around here...
EXIF info:
Nikon D300
Lens: 18-70mm F/3.5-4.5G
Focal Length: 70mm
Aperture: F/4.5
Shutter Speed: 1/125s
ISO Sensitivity: ISO 400