Japan - T League | 03/02 06:30 | - | Koki Niwa v Taimu Arinobu | L | 1-3 | |
Japan - T League | 12/09 06:00 | - | Koki Niwa v Taimu Arinobu | W | 3-2 | |
Japan - T League | 11/17 11:00 | - | Kakeru Sone v Koki Niwa | W | 2-3 | |
Japan - T League | 02/18 04:30 | - | Satoshi Aida v Koki Niwa | L | 3-0 | |
Japan - T League | 02/05 05:40 | - | Koki Niwa v Hiroto Shinozuka | L | 0-3 | |
Japan - T League | 02/04 05:15 | - | Koki Niwa v Kakeru Sone | W | 3-2 | |
Japan - T League | 01/09 04:50 | - | Koki Niwa v Matsushima Teruzora | L | 1-3 | |
WTT - Contender Almaty | 09/16 11:30 | 4 | Koki Niwa v Yuanyu Chen | L | 1-3 | |
WTT - Contender Almaty | 09/15 13:45 | - | Koki Niwa v Cheng-Ting Liao | W | 3-1 | |
WTT Contender Muscat | 09/07 15:30 | - | Benedikt Duda v Koki Niwa | L | 3-2 | |
WTT - Contender - Tunis | 08/04 15:00 | - | Gaoyuan Lin v Koki Niwa | L | 3-0 | |
WTT - Contender - Tunis | 08/03 15:30 | - | Koki Niwa v Jaehyun An | W | 3-1 |
Koki Niwa (Tomakomai, Hokkaido, 10 oktober 1994) is een Japanse professioneel tafeltennisser. Hij speelt linkshandig met de shakehandgreep.
In 2012 (Londen), 2016 (Rio de Janeiro) en 2020 (Tokio) nam hij deel aan de Olympische spelen.