"I was aiming for a podium finish at first, but I changed my target to winning the title after the two Chinese players pulled out," Hirano was quoted as saying by Kyodo news agency.
"It was huge for me to win it when everyone was looking to do so with no Chinese players. I won't be able to win the gold medal if I can't beat Chinese players.
"So I am looking to get used to the Chinese style of play (in order to) start winning."
China won all four gold medals at the Rio Games and Hirano, who watched her Japan team mates win bronze as a reserve, said she was desperate to nail down a starting spot for the 2020 Tokyo Olympics.
"I saw things that are only possible to see from outside, but it was a weird position where I couldn't take part," she added of her Olympics experience.
"Watching my three team mates made me envious in a way, and it also made me feel I want to be there next time at any cost."
(Reporting by Shravanth Vijayakumar in Bengaluru; Editing by Greg Stutchbury)
