まん中: middle

布ぬののまん中まんなかに穴あなをあけて、頭あたまを通とおして着きる服ふく

clothing worn by cutting a hole in the middle of a cloth and putting your head through it

布ぬののまん中まんなかに穴あなをあけて、頭あたまを通とおして着きる服ふくで、貫頭衣かんとういと呼よばれています。

It was a garment worn by passing the head through a hole in the middle of a cloth, and it is called a kantōi.