expression, godan verb (-ku)
begin a new chapter; turn over a new leaf
Idiomatic expression meaning to start something new, often in life, career, or a project. Can be used both literally (a book) and figuratively.
彼は退職後、新しいページを開くつもりだ。
After retirement, he intends to begin a new chapter in his life.
この本の新しいページを開くと、美しい挿絵があった。
When I opened a new page in this book, there was a beautiful illustration.