My father underwent surgery for hemorrhoids.

The last day of the month in the lunar calendar, which is determined by the waxing and waning of the moon, is called Misoka.

I have visited Tsutenkaku.

He is a very famous wrestler in the sumo world.

This problem is just the tip of the iceberg.

Mr. Kagaku is my best friend.

The inner shell of this shellfish is very hard.

The inner enclosure of this castle is very sturdy.

The inner enclosure of this castle was very strong, and it was an important defense line to prevent enemy invasions.

He was observing the inner shell of the clam.