Please use these for reference when training for a marathon. Set of 2 books. Core Running by Tetsuhiko Kin Price: 1200 yen (excluding tax) New common sense of running taught by a charismatic coach Super Easy Marathon Training Method by Kazuhiko Kotani Supervised by Tetsuhiko Kin Price: 1400 yen (excluding tax) 40 amazing techniques that even beginners can use to break 4 hours in 4 months