Genji and Heike clans; two opposing sides
Refers to the Minamoto (源) and Taira (平) clans, especially in the context of the Genpei War (1180–1185). By extension, can mean any two rival factions.
The Genpei War greatly changed Japanese history.
This match is just like a battle between two rival sides.
the four major historical clans: Minamoto, Taira, Fujiwara, and Tachibana
Standard kanji spelling; refers to the Minamoto (源) and Taira (平) clans.
Compound of 源 (Gen, Minamoto clan) and 平 (Hei, Taira clan). The reading げんぺい is a standard Sino-Japanese combination.