Ryogi was the closest Shikadai ever came to having a romantic partner.
I simply love how these two have such good romantic chemistry, even if it only lasted 5 episodes.
They spoke for, at most, a week, probably only 5 days, and yet it was incredible how compatible they were. They understood each other, had similar opinions and common tastes.
There were even scenes and lines that are normally used in romantic scenes, such as Shikamaru asking "Why was Shikadai smiling so much?" And then Shikadai changes the subject, but it was obvious he was thinking about Ryogi. Shikadai isn't someone who gets very attached or even interested, but with Ryogi he seemed really determined. Even though Ryogi hadn't actually said he was going to show up, Shikadai waited for him for two days, until he actually showed up so they could play together.
Later, when Ryogi accidentally drops the Shogi, a gift Shikadai gave him, and Gekko picks it up, there's a scene that's often used to subtly allude to romance; Gekko says that he "understands what's going on between Ryogi and Shikadai," and Ryogi replies defensively, "He means nothing to me."
Furthermore, Shikadai is one of the only characters so far who hasn't shown any romantic interest in anyone, and there isn't any potential character to be his future romantic partner either. Other characters even have options, but Shikadai doesn't, and the closest we've come to that was the Byakuya Gang arc, Shikadai seems somewhat melancholic and mysterious at the end, saying he'll wait for Ryogi to get out of prison. It's a real shame that he never reappeared, and we probably won't hear from him again.
I love my ShikaRyo with all my heart ToT
(CREDITS TO THE ARTIST )
(Fanfic coming soon)