Let Me Forget, Kouhai-kun.

Synopsis

If you see a lucky dolphin, your unrequited love will be reciprocated. That's the legend around these parts. Natsume Shirahama was just having a laugh at the old superstition when a cute girl Umika appeared in front of him wearing a dolphin ornament in her hair. Surely a hair ornament doesn't have anything to do with that, he thought. "I thought if I waited here, I might be able to see Natsume-kun again." Actually he was still pining for Hirose Haru, his old crush, who moved away to Tokyo for college. But as he played with Umika and helped her with her studies, it was almost like old times, except this time it was like his unrequited love was being rewarded. "Sometimes, you look just like Seitarou-senpai." It looks like Shirahama isn't the only one who's trying to get over an old crush? (Source: Sneaker Bunko, translated)