Using a more traditional style, totally different from Mugen's, Jin is just as deadly. Jin's movements are fluid and direct with a lethal effciency lacking in his rival. His sword is his most prized possession and he even refers to it as his "soul." The only time he ever became upset was when Fuu sold his sword to enter an eating contest.
We know several tidbits about Jin's past: First, he's a master at the game of Shogi, a Japanese board game similar to chess. He mentions that he studied it in a dojo. Later, he's found by another swordsman who claimed to have studied alongside him under a master, Mariya Enshiro (who supposedly was undefeated after a thousand duels), whom Jin later betrayed and killed. Jin admits to killing him but says that he "did not betray him." Because there are many other disciples of Enshiro who want Jin's head, he lets the man live to tell them that he's ready and waiting.
Finally, it should be mentioned that, although Jin never wants to sell his sword, Mugen always does. Mugen's sword is always worth nothing and Jin's is rather valuable.