は/が and を with the Passive form


I've recently started learning the passive form of verbs and noticed a few
different usages of particles that have been giving me a lot of trouble and I
wanted to clarify/confirm.

From what I've gathered from my book and this site, when を is used with the
passive form of a verb it implies that a person (subject marked with は) was
affected in some way by the individual acting out the verb (marked with に）。

  1. 僕は妹に日記を読まれました。  
→ My sister read my diary and it has bothered me.

  2. 僕は妹に部屋を掃除された。  
→ My little sister cleaned my room.

From my understanding because 日記 and 部屋 are marked with を it adds the
implication that the subject/topic of the sentence (僕) is the owner of the 日記
and 部屋 since he was affected by his little sister acting out the verb. Is this
correct?

However, I have seen examples where the subject (marked with が) seems to be
the object/undergoes the change carried out by the verb instead of being
marked with を. (Both the subject and the direct object can undergo the
change?)

  3. 日記が妹に読まれました。  
→ The diary was read by my little sister.

  4. 部屋が妹に掃除された。  
→ The room has been cleaned by my little sister.

In example 3 and 4, from my understanding these examples imply that the diary
was read by the sister and the room was cleaned by the sister (diary and room
undergoing the change), However since these are NOT tagged with 僕は(or some
other individual) it is not implied that these do not belong to someone else.
I.E. The diary being read and the room being cleaned do NOT affect an unnamed
individual. And because of this from my understanding sentence 3.) and 4.)
would be essentially the same in meaning as 5.) and 6.), basically this is
just another way of saying the same thing?

  5. 妹は日記を読みました。  
→ My little sister read the diary.

  6. 妹は部屋を掃除した。  
→ My little sister cleaned the room.

Is this correct?

Finally there's no way that を in examples 1 and 2 can be replaced with が to
make an equivalent sentence is there?

  7. 僕は妹に日記が読まれました。  
→ My sister read my diary and it has bothered me.

  8. 僕は妹に部屋が掃除された。  
→ My little sister cleaned my room.

Do sentences 7 and 8 make any sense or are they unnatural and grammatically
incorrect? Can が and を be used interchangeably at all in these types of
sentences?




> _From my understanding because 日記 and 部屋 are marked with を it adds the
> implication that the subject/topic of the sentence (僕) is the owner of the
> 日記 and 部屋 since he was affected by his little sister acting out the verb. Is
> this correct?_

Yes. But maybe your understanding about why it works in that way is not enough
correct. 僕は in your example #1 and #2 is a topicalization of underlying 僕が,
which is clear if you put these sentences into subordinate clauses.

> 1'. 僕 **が** 妹に日記を読まれたのは、先週でした。  
>  2'. 僕 **が** 妹に部屋を掃除されたのは、先週でした。  
>  "It was last week that ..."

As you can see, it's essentially the same composition as your #3 and #4.

> _However since these are NOT tagged with 僕は(or some other individual) it is
> not implied that these do not belong to someone else. I.E. The diary being
> read and the room being cleaned do NOT affect an unnamed individual._

As an aside, this statement may not always be true. We often omit the known
participants in discourse, so hearers usually bear the possibility in mind.
Moreover, lack of topic in your examples makes them more suspicious of
existence of hidden topic. (Besides, is it likely that a diary already written
belongs to nobody?)

> _And because of this from my understanding sentence 3.) and 4.) would be
> essentially the same in meaning as 5.) and 6.), basically this is just
> another way of saying the same thing?_

Not really. Japanese language is quite strict on [animacy
hierarchy](https://en.wikipedia.org/wiki/Animacy), that prefers human, animal,
(maybe robot,) and other "alive" things for the subject of a sentence. It's
not impossible to override, but doing so needs reasonable cause.
`日記が多くの人に読まれている` in user4092's answer is valid, because in this case `多くの人` is
almost impersonal that not worth focussing if you're talking about the diary.
Your examples, especially #3 is pretty hard to come up with an appropriate
situation at first glance, unless that you're an undercover using the diary as
an important secret communication tool or something.

> _Do sentences 7 and 8 make any sense or are they unnatural and grammatically
> incorrect? Can が and を be used interchangeably at all in these types of
> sentences?_

Very unnatural. The only possible interpretation of #7 and #8 is that 僕は is an
"true" は, as in `象は鼻が長い` "Elephants have long trunks", but then the semantics
could be bizarre: did he suffer some physical damage, or the stigma of "man
whose diary is read by his sister"?

