千せん番ばんに一いち番ばんの兼かね合あい

Meanings

extremely difficult; a one-in-a-thousand chance

rare term

Rare idiomatic expression emphasizing that success is so unlikely it is almost impossible. Used to describe a situation where the odds are overwhelmingly against you.

この難なん問もんは千せん番ばんに一いち番ばんの兼かね合あいだ。
This difficult problem is a one-in-a-thousand chance.
彼かれが試し験けんに合ごう格かくするのは千せん番ばんに一いち番ばんの兼かね合あいだろう。
The odds of him passing the exam are extremely slim.

Kanji

千thousand
番turn, number in a series
一one, one radical (no.1)
兼concurrently, and, beforehand
合fit, suit, join

Related words

千せんに一ひとつの兼かね合あい
A similar expression meaning 'one in a thousand', but less emphatic than 千番に一番の兼ね合い.

Built from

千せん番ばん+一いち番ばん+兼かね合あい

Written forms

千せん番ばんに一いち番ばんの兼かね合あい
Standard kanji form for this idiomatic expression.
千せん番ばんに一いち番ばんの兼かね合あい
Variant with simplified kanji for 兼ね合い.

Etymology

The expression literally means 'a balance of one in a thousand attempts', combining 千番 (a thousand times) and 一番 (one time) with 兼ね合い (balance, likelihood). The exact origin is uncertain, but it likely developed as a figurative way to express extreme improbability.