Confusing 届ける　受身 form


I'm having trouble understanding why "手紙がTofuguオフィスに届けられた" is translated into
"The letter was sent to the Tofugu office". In my head it should be translated
as "The letter was sent by the Tofugu office" because of the passive + に
construction.

What am I missing here?

Thanks in advance.




The particle に has various functions, and some verbs safely take に in active
(i.e., non-passive) sentences. As you know, に in active sentences are
typically translated as "to ～".

>   * 手紙をTofuguオフィス **に** 届けた。  
>  I delivered the letter **to** the Tofugu Office.
>   * 漢字を黒板 **に** 書いた。  
>  I wrote a kanji **on** the blackboard.
>

When such sentences are turned to passive sentences, these ～に are left
unmodified, and still play the same role of the original active sentences.

>   * 手紙がTofuguオフィスに届けられた。  
>  The letter was delivered to the Tofugu Office.
>   * 漢字が黒板に書かれた。  
>  A kanji was written on the blackboard.  
>  (Not "A kanji was written by the blackboard")
>

Usually, you can use common sense and safely determine the meaning in one way.

* * *

Obviously, this may lead to ambiguity in some rare cases.

>   * 彼女を社長 **に** 紹介した。 I introduced her to the president.
>

The passive version is:

>   * 彼女が社長 **に** 紹介された。  
>  She was introduced **to** the president.  
>  She was introduced **by** the president.
>

Both seem possible, and this sentence is actually ambiguous. You need to
determine the correct interpretation from the context. (If you already know
relative clauses, 社長に紹介された人 can mean both "the person introduced to the
president" and "the person introduced by the president".)

When this really matters, or when you need to avoid using に twice, you can use
によって instead of に to disambiguate. See: [How to use
紹介される?](https://japanese.stackexchange.com/q/37097/5010)

>   * 漢字が先生によって黒板に書かれた。  
>  A kanji was written on the blackboard by the teacher.
>   * 手紙がFedExによってTofuguオフィスに届けられた。  
>  A letter was delivered to Tofugu office by FedEx.
>

