筆ふでを起おこす

expression, godan verb (-su)

start writing; begin to write

Idiomatic expression used when someone begins writing a book, article, or other substantial piece of writing. Often implies a formal or literary context.

• 作さっ家かは新あたらしい小しょう説せつのために筆ふでを起おこした。

  The author started writing a new novel.