The eruption occurred on Mount Fuji 's east -- north-east flank and formed three new volcanic vents , named No. 1 , No. 2 , and No. 3 Hōei vents .
The eruption was on Mount Fuji 's east -- north-east slope and made three new volcanic openings called No. 1 , No. 2 , and No. 3 Hōei vents .