While reading about passive sentences, I came across this example (from http://www.imabi.net/passiveii.htm):
私が河田に水藤へ藤原を紹介された。
Kawada introducing Fujiwara to Suito was inconvenient to me.
My basic understanding of this “indirect passive” sentence is as follows: the action “introduce Fujiwara to Suito” (水藤へ藤原を紹介する), was done ‘to me’ by Kawada (私が河田に combined with passive verb), where the action being done ‘to me’ implies that it indirectly affects me in a possibly unforeseen or unwanted way. Is this a good way of thinking about it?
This particular sentence struck me because the directional particle へ is used with 紹介する, which as far as I can tell is not usually considered a verb of motion. Surely “introduce Fujiwara to Suito” would normally be 水藤に藤原を紹介する, and as such I might be tempted to rewrite the example sentence as
私が河田に水藤に藤原を紹介された。
Now, since the two targets marked with に have completely different roles, would this sentence be ambiguous? If so, I can see why it would make sense to change the second に into an へ in order to differentiate. The grammatical role of 水藤 is certainly much more similar to “directional target” than that of 河田. This raises the question of when this change is allowed. Is it particular to 紹介する? Or maybe, in indirect passive sentences where the agent performing the action is marked with に, is it always correct to change occurrences of に marking direct targets of the action to へ? This would give examples such as
私が友達にみんなへ秘密を教えられてしまった。
My friend told everyone my secret. (I wasn’t happy about this.)
Since I find this interesting, I spent some time thinking about how far I could push it. Is it possible to make this change from に to へ even if the に is being used to convert an adjective into an adverb? So:
部屋が真っ暗闇になった。
The room went pitch black.
私が部屋に真っ暗闇へなられた。
The room went pitch black on me.
I’m fairly skeptical about this last sentence, since even without changing に to へ, it’s probably clear to any reader that it is the room which becoming pitch black, not the pitch black which is becoming a room. But I’m sure there are similar situations (maybe with a verb other than なる) where such ambiguity could exist.
One final question, if I’m not completely misinterpreting this: are there any other situations where に can be changed to へ for grammatical reasons?
Sorry for the long post. I’m still relatively new to learning Japanese, so all of this might be entirely wrong. Any clarifications or references related to the these topics would be much appreciated!