noun
inside baseball
A baseball term referring to strategic, detail-oriented play; also used figuratively for insider knowledge or complex details in any field.
彼の解説はインサイドベースボールすぎて、初心者には難しかった。
His commentary was too inside baseball and was difficult for beginners.
この議論はインサイドベースボールだ
This discussion is inside baseball, so outsiders probably won't understand it.