The big wooden fish called Hô is used principally in the Sôtô monastery. The inside is hollowed out. It is used to announce the midday meal.
The "wooden fish" is a percussion instrument made of a hollow wooden block originally used by Buddhist priests to beat rhythms when chanting scriptures.
These are two kinds of wooden fish: one is round with carved scales and the other is rectangular and suspended in front of dinning halls of Buddhist temples. It is said that fish don't close their eyes when sleeping to remind the chanting monks to concentrate on when they are doing. When having breakfast and lunch, the monks beat the latter type of wooden fish to produce a rhythm the monks call the "Bang."