It is the story of Kume no Heinai, a samurai who lived at the beginning of the Edo period. On reaching old age, he decided to become a Zen monk, wishing to hold religious memorial services to honor the samurai he killed in battles.
At the end of his life, he requested his followers to carve his face on a rock, and to bury it next to the Niomon Gate. By then, the Senso-ji temple was already one of the most circulated areas in Edo, and he wanted his effigy to be stepped on by as many people as possible, as a repentance for his past killings.
After a while, the carving was moved inside a small temple erected nearby, called Kume-no-Heinai-do, photographed here...
EXIF info:
Nikon Df
Lens: 24-70mm F/2.8G
Focal Length: 26mm
Aperture: F/2.8
Shutter Speed: 1/60s
ISO Sensitivity: ISO 3200