"Train Your Brain! Riddles for 1st and 2nd Graders" Yasuyuki Taki Price: ¥700 #YasuyukiTaki #Yasuyuki_Taki #Book #Lifestyle/Hobbies & Entertainment First Grade, Elementary School I already have a copy of this book, so I've only flipped through this one. The level is just right, and it's a fun book to do with your kids.