両方ともよい。

English Translation

They are both good.

What is the grammatical purpose of とも in this sentence? why wouldn’t a simple も or other particle suffice?

I think 両方とも is a single word、like 二人共 (ふたりとも).

共 may mean “both” or “together”. It is strange that both my dictionary and my IME both use kana for one and kanji for the other, but I think the meaning is the same in both cases.

So both words appear to mean “the two together”. Although 二人共 refers specifically to people, While 両方とも seems to mean more “both sides”.

1 Like

とも is derived from ともに. とも in this sentence structure is NOT particle と (to/toward) + particle も (too).

両方とも良い is a shorten form of 両方ともに良い. We don’t spell it as in Kanji 両方 (に)良い in this particular sentence, though.

  • 共に in Kanji means “together”. In other words, the condition (e.g. good, nice) is not applied to only one side. If the counterpart is missing, the one alone is not good/nice. That’s the meaning of 共に in Kanji.

  • ともに in Hiragana means “not only A but also B” or “A as well as B”. A is still good/nice even if B is missing when you say ともに in Hiragana.

Example sentences:

メアリーはトムと共に海に行った。= Mary went to the beach with Tom. = Mary and Tom were in a group.

メアリーとトム、両者とも頭が良い。= Both Mary and Tom are smart. = Mary would be still smart even if Tom passed away.

1 Like