up to scratch

Haruki Murakamiの小説 "South of the Border, West of the Sun" を読んでいます。

During the day I'd take care of all sorts of chores, then at night I'd make the rounds of my two bars, checking out the cocktails to see that they tasted right, watching the customers' reactions, making sure my employees wore up to scratch. And I listened to the music.

"up to scratch" は従業員の着ている服装についてのことですが、意味を調べます。

・Collins Dictionary: If you say that someone or something is not up to scratch, you mean that they are not good enough.: My mother always made me feel I wasn't coming up to scratch.
・Cambridge English Dictionary: reaching an acceptable standard: come up to scratch Your last essay wasn't up to scratch/didn't come up to scratch.
・Oxford English Dictionary: sufficient; adequate; of acceptable or satisfactory quality: They decided that his performance was not up to scratch.

"from scratch" はよく聞きますが、"up to scratch" でこの様な意味になるのが不思議で語源を調べるとMerriam-Websterに次の説明がありました。

Incidentally, the phrase "up to scratch," which means "of a satisfactory condition, level, or performance," is several decades newer than "up to snuff," and has its origin in pugilism: at the beginning of the match and each round, boxers were required to stand with their toes against the scratch, a line drawn across the prize ring. A boxer who could not do so was unable to come up to scratch, and therefore not up to snuff.

この説明に出てくる "up to snuff" は8/9/2013に取り上げていました。