Passive verbs (finally) started making perfect sense to me once I examined them using tiny relative clauses. For example:
- 選ばれた人
This is 選ぶ (えらぶ, to select) in passive form, and means “the person chosen/selected.” The 人 in this example did not 選ぶ anything, because… the verb passively happened to them. Note that 選んだ人 by comparison, without the passive form, is actually ambiguous and, depending on context, may refer to either the chooser or the person chosen.
I never used Tae Kim’s stuff very much, but it looks like he’s got a pretty good piece about the Japanese passive here:
The Japanese word for “passive”,「受身」(うけみ), using the characters for “receive” and “body” expresses what the passive is in Japanese; people are doing things to you and you have no choice but to take it like a bitch. The passive indicates that the action was not done by the subject but done unto the subject. In other words, the subject had no control or input on the action.
I edited it a bit to make more sense out-of-context and added my own emphasis, but if you want to read the original, you can find it here: Don’t Suffer Passively