山やまを張はる

expression, godan verb (-ru)

speculate; make an educated guess; gamble on a hunch

Used when someone bets on a likely outcome based on intuition or partial information, often in contexts like exams, predictions, or risky decisions. The related expression 山を掛ける is similar.

See also: 山をかける

• 試し験けんに出でそうな問もん題だいを山やまを張はって勉べん強きょうした。

  I studied by guessing which questions might appear on the exam.

• 彼かれは選せん挙きょの結けっ果かを山やまを張はって、見み事ごとに当あてた。

  He speculated on the election results and got them exactly right.