Q. What does "- chau" mean at the ending of some verbs? What is the difference between "suru" and "shichau"?
A. "~ shichau （~しちゃう）" is a very colloquial expression that means "to have done". Since it is informal and sounds childish in a way, it should not be used when speaking to superiors. The formal form of "~ shichau" is "~ shite shimau （～してしまう）". The verb "te form" and "~ shimau （～しまう）" are combined to make this form. It expresses a complete action.
| Basic form | Te form | Complete action | |
| Formal | Informal | ||
| suru (to do) する |
shite して |
shiteshimau してしまう |
shichau しちゃう |
| iku (to go) 行く |
itte 行って |
itteshimau 行ってしまう |
icchau 行っちゃう |
| kiku (to listen) 聞く |
kiite 聞いて |
kiiteshimau 聞いてしまう |
kiichau 聞いちゃう |
Compare these sentences.
| Hiroshi wa nihon ni itta. 博は日本に行った。 (Hiroshi went to Japan.) |
Hiroshi wa nihon ni itteshimatta. 博は日本にいってしまった。 (Hiroshi has gone to Japan.) |
| Kono hon o yonda. この本を読んだ。 (I read this book.) |
Kono hon o mou yondeshimatta. この本をもう読んでしまった。 (I have already read this book.) |
| Sono penki o tsukatta. そのペンキを使った。 (I used the paint.) |
Sono penki o zenbu tsukacchatta. そのペンキを使っちゃった。 (I have used all the paint.) |
