expression, godan verb (-su)
be obvious; be clearly correct
Idiomatic expression meaning something is so obvious it's like pointing to the palm of one's hand. Often used when the truth or correctness of a matter is self-evident.
彼が嘘をついているのは掌を指すように明らかだ。
It's as clear as pointing to your palm that he is lying.
その答えは掌を指すほど簡単だった。
The answer was so obvious it was like pointing to your palm.