The Main Gauche is a dagger in Final Fantasy XII. Most weapons in the game boost Evasion, but Main Gauche grants the most significant increase to Evasion for a one-handed weapon. In the original version the only weapons with a greater Evasion are the single increase Defender greatsword, and the greatsword Wyrmhero Blade. In the Zodiac versions its Evasion is increased even further, such that it is only equalled by the Wyrmhero Blade, and only bested by the bow Seitengrat.
In the Zodiac versions the Main Gauche is penalized in its combo rate, being much less likely to spawn combos than other daggers. Its license is learned by Shikari for 35 LP in the Zodiac versions, or everyone in the original for 30 LP.
Weapon evasion functions like shield evasion, blocking away only physical attacks. In the menu the weapon's Evasion is added to the Evasion granted by the shields, but the game only checks for weapon evasion when the shield evasion fails.
Tougher bosses and marks can ignore blocking and parrying completely.
Main gauche means "left hand" in French. The Main Gauche is the name given to a parrying dagger wielded with the left hand, which was used in the late Middle Ages and early Renaissance, as an off-hand weapon in conjunction with a sword.