Shukichi Haneda and Yumi Miyamoto first met when the latter was still in college, and had begun dating since then until Yumi eventually broke up with him because she thought he was immature. Shukichi is completely oblivious to Yumi breaking up with him and he still thinks of her as his girlfriend as if nothing has happened. Yumi, on the other hand, refers to him as an ex and doesn't show much interest in his personal life. Despite this, it appears she still has some feelings for him.
Their relationship began to relapse after Shukichi was caught up in a murder case in his apartment complex. Despite Yumi acting standoffish most of the time, they start using pet names for each other once again. They even exchanged a kiss before Shukichi continued his shogi match to win the seventh title. By the time Yumi figured out Shukichi's real identity, Shukichi was regularly meeting with her. All of this time, Yumi still insisted on calling him an ex.
Yumi was unaware of Shukichi being a famous shogi player for a long time, mostly due to her lack of interest in investigating, and an apparent personal disinterest in shogi (she is more of a Mahjong type). She assumed Shukichi was a "meijin" at some minor game like shiratori or fishing. She eventually saw Shukichi on television and figured it out. After realizing that meijins can make 100,000,000 yen in salary, she desperately tries to reclaim the letter he left for her, which her ornery building manager had seized.
After Shukichi lost the decisive match against Chikara Katsumata,Yumi rips the letter on Shukichi's favour as it became invalid due to his loss. Disappointed by his loss, Yumi encouraged Shukichi that she will wait for him to re-gather the seven Shoji titles once again and that she will listen to any one of his wishes. She also motivated him to never lose to anyone, improving the romantic relationship between the two.