My grandfather used to till his privately-owned rice field.

He holds a personal grudge against me.

Using the private railway makes commuting very convenient.

He trains every day with a bokken.

Fir trees beautifully color the winter landscape.

Kimiko is my best friend.

He continues to hone his calligraphy skills.

Mr. Iriki is my best friend.

Understanding the algorithm of the regression tree is difficult.

A decision tree is a part of machine learning and a model for classifying or regressing data.