noun
trifling fight; petty conflict between small parties
A yojijukugo derived from a classical Chinese fable about a battle fought on a snail's antenna, used to describe a trivial quarrel or a conflict between insignificant parties. Literary and idiomatic.
彼らの言い争いは、まさに蝸牛角上の争いだ。
Their argument is nothing more than a petty squabble.
A longer, more explicit form of the same idiom, literally 'a fight on a snail's horn'.
From a classical Chinese fable in which two kingdoms fight on the antennae of a snail, illustrating the pettiness of human conflicts. The exact historical derivation is uncertain, but the phrase is a well-known yojijukugo in Japanese.