This is a book that teaches strategies to improve your winning rate. - Title: What to Discard to Increase Your Winning Rate by 5% - Supervision: Takeshi Kobayashi - Price: 1500 yen - ISBN: 978-4-8019-2191-0 I intended to learn hand efficiency from this book, but I started attending a mahjong class where I learned through practice, so I barely read it. Therefore, it's almost unused. Thank you for looking.