最さい古こ

noun, noun which may take the genitive case particle 'no'

the oldest; the earliest

Refers to the single oldest or earliest known example of something, often used in historical, archaeological, or record contexts.

• これは現げん存ぞんする最さい古この写しゃ本ほんです。

  This is the oldest surviving manuscript.

• その寺じ院いんは日本にほん最さい古この木もく造ぞう建けん築ちくと言いわれている。

  That temple is said to be the oldest wooden building in Japan.