godan verb (-u), intransitive verb
clash; collide; conflict; coincide
Used for schedules, events, or opinions that clash or overlap in an undesirable way. Can also refer to physical collision, but more often abstract.
会議の時間がかち合ってしまった。
The meeting times clashed.
彼の意見
His opinion conflicted with mine.
godan verb (-u), intransitive verb
meet by chance; come across; run into
Refers to unexpectedly meeting someone or encountering something. Often used for chance encounters with people.
駅で偶然、昔の友達とかち合った。
I ran into an old friend by chance at the station.