The effects of Hasso and Seigan do not overlap. If both abilities are used, only the most recently activated ability will take effect.
Hasso will only take effect when the player is equipped with a two-handed weapon (Hand-to-hand weapons do not count as two-handed weapons in this case).
A penalty will be imposed on magic, song, and ninjutsu casting while Hasso is in effect. This penalty is a 50% increase in casting time and recast time.
A level 75 samurai will gain a boost of +10 STR, +10 Accuracy, and +10% haste for melee attacks. The STR boost is based on the level of the Samurai (At Lv.25, the boost is +3 STR, but at Lv.75, the boost is +10 STR.) When SAM is set as a subjob, the STR value is as would be for a SAM of that level; i.e., for a MAIN75/SAM37, Hasso will boost STR by 5, as SAM receives a +5 at 37. Other boosts remain constant.
Hasso's +10% melee haste effect will not reduce the amount of TP gained per hit.
Hasso's +10% melee haste effect is considered Job Ability haste.