ものをBut, Although, If only, I wish I had

ものを is a grammar point that functions in a similar way to のに in that it will express that (A) is something that was desired, despite (B) being the actual result. However, it is primarily used when the speaker is trying to convey their displeasure at the result of (B), due to (A) being something that by all means should have happened.

ものを will be translated as 'if only (A)', or '(A), but (B)'. Despite being a construction of もの and the adverbial particle を, ものを is often considered as a standalone conjunction particle. It can be seen following verbs or い-Adjectives in their standard form, or な-Adjectives followed by な.

• もっと早(はや)くに歯医者(はいしゃ)に行(い)けば歯(は)を抜(ぬ)かずに済(す)んだものを...

  If you went to the dentist earlier, they wouldn't have had to remove your tooth, but…
• 目(め)を合(あ)わせなかったら止(と)められなかったものを、なんで警察(けいさつ)なんかと目(め)を合(あ)わせちゃうんだ。

  If only you didn't make eye contact with the police, we wouldn't have been stopped, so why did you have to go and make eye contact with them?
• アレルギーなどがあったなら、さきに言(い)ってくれればいいものを...

  If you had an allergy, you should have let me know beforehand, but…
• 「手伝(てつだ)って」って言(い)えばいいものを、一人(ひとり)でやるからこう言(い)う目(め)に遭(あ)うんだよ。

  If you have just asked for help, but because you did it alone, it ended up like this.
• みんなでやれば簡単(かんたん)なものを...

  It would have been easy if we all worked on it together, but…
• 道具(どうぐ)を使(つか)えば楽(らく)なものを、わざわざ自分(じぶん)の力(ちから)でやろうとするから怪我(けが)をするんだよ。

  It would have been easier if you used tools, but because you went out of your way to try it without any tools, you ended up getting hurt.

As can be seen in the above examples, ものを is almost always preceded by hypothetical structures such as ば at some point leading up to its use.

Caution

ものを will often be seen at the end of sentences, with what would have come after it being left unspoken. In these cases, the important information is still there, as the (A) part of the sentence will always highlight what the ideal result was. Because of this, it can be safely assumed that the speaker is just frustrated that (A) didn't happen.

• 素直(すなお)に認(みと)めていればいいものを...

  I should have just been honest, but… (I should have just been honest, but instead I continued to lie)

Fun Fact

The adverbial particle を is often used this way in Japanese, where no specific action is linked to it. In these situations it usually just indicates an ideal or goal to which the method of achieving it (the verb that would usually be attached to を) is omitted. ものを can be thought of as an extension of this in literally meaning 'to that which was (A)', with 'I wish it had happened' being unsaid.

• 政治(せいじ)ポスター： 「日本(にほん)を前(まえ)へ。」

  Political poster: Japan forward. (Verb omitted but obvious from context, the positive improvement of Japan)