1.
paperback book, bunko-format book
A small, affordable paperback book in the standard Japanese bunko format (approximately A6 size, 105 × 148 mm). A distinctive feature of the Japanese publishing industry, bunko editions are typically reprints of hardcover books released at a lower price point.
Since the hardcover is expensive, I decided to wait until the paperback comes out.
Usage
A compound of 文庫 (library/collection) and 本 (book). The bunko format is a staple of Japanese publishing — major publishers have their own bunko lines (e.g., 新潮文庫, 角川文庫). Bunko books are typically priced around ¥500-800, significantly cheaper than hardcovers. They are popular for reading on trains due to their compact size.