looking for rivalry to romance hjstorical Yaoi

I’m trying to remember this historical yaoi I read. The story starts with the mc’s dad, who was a respected guy in their village. One day he finds the ml, an orphan, and brings him home.
As they grow up, mc is always competing with ml because he’s jealous of how close ml is to his dad. One day they go to the lake to bathe, and while they’re there, their rivalry turns into sexual tension. Later, mc gets curious about gay sex or straight and buys a book about it. ml sees it and teases him That night, while they’re in the same room trying to sleep, they end up having sex. That was their last peaceful day together, because soon after, the village gets attacked, and mc and ml get separated. It takes years before they can be happy again mc has brown hair, ml has black hair. I remember these events pretty clearly and I really want to find the name of this manga.