also: クモがっせん
noun
spider fighting
A traditional pastime, especially among children, where spiders are made to fight each other. Often associated with the spider species Argiope amoena (コガネグモ).
昔の子どもたちは、よく蜘蛛合戦をして遊んだ。
Children in the old days often played spider fighting.
蜘蛛合戦に使うクモは、コガネグモが一般的だ。
The spider commonly used for spider fighting is the Argiope amoena.
Compound of 蜘蛛 (kumo, 'spider') and 合戦 (kassen, 'battle'). The reading がっせん is a rendaku form of かっせん.