The child was the son of the chief. Were there any similar novels where the male protagonist transmigrated into the body of a child of a tribal chief in Africa (the child was the son of the chief)?

In the time-travel novel, the male protagonist was transported to the child of a tribal chief in Africa (This child's head was broken because the tribe was plundered, right?) I remember that he told the tribe how to train the children and asked his mother to make military uniforms for them. Then, when their tribe moved to the place, he told them how to build fortifications. Then, the chief asked him how he knew. He said that he did not want his head to be smashed again, so he came up with it. That's all. Who knows what novel it is? At the beginning of the novel, there must be no magical beasts or anything like that. It's just a primitive tribal fight or something.