This is the simplest yagura type. It's too short to be used as a lookout tower and not usually used as a sumiyagura. Hirayagura is most frequently used on the edge of an outer bailey like a sannomaru bailey that has no dirt walls. It is also frequently used as a connecting yagura to join gates, larger yagura or main keep.
Tamonyagura is a hirayagura that has been stretched out. It can be used in place of dirt walls atop moats and embankments. Tamonyagura are often found connected to corner sumiyagura or main keep. They can be used to store goods, but also function as a very strong defensive platform.