back to square one

Adjective

idiomatic not-comparable

(idiomatic) Located back at the start, as after a dead end or failure.

Japanese Meaning

原点に戻る / 振り出しに戻る / 一からやり直す

Their progress was back to square one after the server crash wiped out the latest builds.

サーバーのクラッシュで最新のビルドが消え、彼らの進捗は振り出しに戻ってしまった。

Sense（1）

(idiomatic) Located back at the start, as after a dead end or failure.