Transitivity

Japanese verbs often come in pairs: Transitive (doing something to an object) and Intransitive (something happening).

Transitive (Tadoshi)
Target: Subject acts on an Object.
Particle: WO (を)

"I open the door."

Door o akeru.
Intransitive (Jidoshi)
Target: Subject changes state.
Particle: GA (が)

"The door opens."

Door ga aku.
Common Pairs
MeaningTransitive (Action)Intransitive (State)
OpenAkeru (開ける)Aku (開く)
CloseShimeru (閉める)Shimaru (閉まる)
Turn OnTsukeru (つける)Tsuku (つく)
Turn Off/EraseKesu (消す)Kieru (消える)
DecideKimeru (決める)Kimaru (決まる)
BeginHajimeru (始める)Hajimaru (始まる)
2hongo - Japanese Dictionary with Context