She then moved up to the 57 kg weight class and contributed to the team's second place finish in the 2016 Jitsugyo team competition against Komatsu, defeating the previous year's Kodokan Cup winner, Ji Ishikawa, with a giai (a technique ari).
At the Asia Open Taipei, she lost in the final to Eimi Kaneko of the Japan Self-Defense Forces Physical Education Academy, and finished second.
After that, she joined Fighter's Flow, which was run by Takao Ueda, a mixed martial artist she knew.
At this time, she was described as a beautiful woman with a small face and a muscular body, but also flexible enough to perform leg openings and Y-balances.
In 2017, she participated in KUNOICHI, a female version of SASUKE aired on TBS, twice in a row, both times achieving top results.
[9] On December 29, 2017, she fought Shizuka Sugiyama at Rizin World Grand Prix 2017: 2nd Round and won a 3-0 decision.
[10] On March 10, 2018, Kana Watanabe took part at Deep Jewels 19 event versus Yukari Nabe.
[11] On August 26, 2018, she won the fight versus Asami Nakai at Deep - 85 Impact event by Submission (Armbar) in Round 1.
[13] On March 8, 2019, Kana Watanabe won her fight versus Soo Min Kang at Deep Jewels 23 by TKO (Punches) in Round 1.
[15][16] On October 22, 2019, she won the fight versus Hee Eun Kang at Deep Jewels 26 by Submission (Rear-Naked Choke) in Round 1.