japanese way of describing 'piece of cake'
 

there is a saying in korea that when something is easy, it's "easier than eating a rice cake lying down." What would be the Japanese saying for this?

Wrong forum. This belongs in the Language section.

The ansｗer is 朝飯前.

Has been moved to the proper section - Nyororin

ちょうはんぜん? It's pretty cool how Korea's and Japan's are the same.

Also if you get rid of the 飯, it sounds like the Japanese word for Korea (a bit): ちょうせん.

i think the reading is あさめしまえ

never heard this before and i don't get it, but i guess "piece of cake" makes no sense either.

It's read あさめしまえ and it's a common phrase used to say something is so easy to do that you can do it even before eating breakfast.　

「こんな翻訳、朝飯前だよ。(a moment passes) はい、できた。」

「自転車のパンクの修理なんて朝飯前ですよ。もう何回 もやったことがあるので。」

lol, 朝飯前?interesting :D never ever heard of it before.