Does 児戯 have the same idiomatic value in Japanese as "child's play" does in English?


In English, "child's play" can literally mean "play performed by a child" or
it can be used as an idiom to refer to "something easy".

I see that Japanese 児戯 can also mean 子供の遊び (児の戯れ, I guess?) - but can it also
be used as an idiom to refer to "something easy"? I suppose you could always
use a "simile"-type construction, like 「その試験は児戯のように簡単だった」, but would I be
clearly understood if I were to say something more terse like 「その試験は児戯だった」
(cf. slightly unnatural English "That exam was child's play")?




児戯 is an uncommon and difficult word. 児戯のように簡単 would make sense as a literary
expression, and I won't be surprised if I see this in old novels. But if you
say this in a conversation today, people would probably say "ジギって何?"

子どもの遊びのように簡単だった is not something people usually say, but it does make sense
and better than 児戯 anyway.

There are at least two similar idioms in Japanese: 赤子の手をひねる and 子どもだまし.

[赤子の手をひねる](http://eow.alc.co.jp/search?q=%E8%B5%A4%E5%AD%90%E3%81%AE%E6%89%8B%E3%82%92%E3%81%B2%E3%81%AD%E3%82%8B)
(lit. "twisting a baby's arm") is an idiomatic and metaphoric phrase that
expresses how easy something is.

> テストは赤子の手をひねるように簡単だった。  
>  テストは赤子の手をひねるような簡単さだった。

But I think it's rarely used in daily conversations, either.

[子どもだまし](http://eow.alc.co.jp/search?q=%E5%AD%90%E3%81%A9%E3%82%82%E3%81%A0%E3%81%BE%E3%81%97)
is used when there is something difficult/complicated/interesting for
children, but too simple for adults.

> テストは子どもだましみたいなものだったよ。

This sounds natural, although it may have a slightly different nuance.

