ばよかった

The structure ～ばよかった is used to express regret about something that was not done, or a wish that things had gone differently. It translates to "I should have…", "I wish I had…", or "it would have been better if…".

It is formed by combining the ば-conditional form of a verb with よかった (the past tense of いい/よい), literally meaning "it would have been good if…".

Regretting not doing something

The most common use is to express regret that you didn't do something.

Regretting doing something

To express regret about something you did do, use the negative ば-conditional (なければ) + よかった.

Adding のに for emphasis

Adding のに at the end strengthens the feeling of regret or disappointment, implying "…and yet (things didn't turn out that way)."

Notes

• This pattern is used to talk about past situations only, since よかった is in the past tense.

• The subject is often the speaker, but it can also be used to express regret on behalf of others or to give hindsight advice.

• The polite form simply adds です after よかった:

  はやく早くいえば言えばよかったです。

  I should have said it sooner.