Malbim: Initially they did not intend to fight with swords, rather, each held the other's head, like wrestlers, and amidst this, each one inserted his sword in his opponent's side, and they both fell, like "Poter Mayim Reishis Madon" (Mishlei 17:14; what begins as a minor matter become a growing feud).

Rashi citing Targum Yonasan: It is the inheritance of the dead. [It says] "ha'Tzurim" due to the [Radak - sharp] swords, like "Af Tashiv Tzur Charbo" (Tehilim 89:44).

Radak #1: It is the plain of the dead, like "Chelkas ha'Sadeh" (Bereishis 33:19). swords, like "Af Tashiv Tzur Charbo" (Tehilim 89:44).

Radak #2: "Ha'Tzurim" is like the simple meaning (rocks, i.e. Giborim), like "veha'Tzurim Nitetzu Mimenu" (Nachum 1:6). It is the plain of the strong ones, for they were strong, and they fought strongly, and neither overpowered the other, rather, they were killed together.