This is the 9897th most frequent Japanese word.
誤算
Miscalculation; error in calculation or judgment.
In this sentence, '誤算' is used to describe an error in numerical or strategic calculation attributed to the plan's failure.
彼の計画は誤算により失敗してしまった。
His plan failed due to a miscalculation.
Here, '誤算' indicates an incorrect estimation or expectation in financial or performance terms.
期待していた売上が誤算だった。
The expected sales turned out to be a miscalculation.
In this usage, '誤算' is used metaphorically to portray an error in anticipating someone's response or behavior.