Uho tau/en

Mei he Wikipedia

In traditional Tongan society it was quite normal for a man (especially a chief) to spread his seed over several women. In this way he avoided (sometimes fatal) jealousy between the different families. Later when his sons had grown up he would select the best one to succeed him in his position. By consequence all these sons were rivals, vying for their father's blessing. As such the term uho tau - fighting navelstring - for brothers with the same father but different mothers. FOKI