almost on a par; neck and neck; referring to two people or things whose ability or quality is nearly identical

(idiom) to be equally matched; to be so similar in talent or ability that it is impossible to distinguish a winner; literally "unable to distinguish the eldest brother from the second brother"

(idiom) The sequence of seniority for brothers in ancient China, where [[伯|伯|bo2]] is the eldest, [[仲|仲|zhong4]] the second, [[叔|叔|shu1]] the third, and [[季|季|ji4]] the youngest.