AFAIK: Martial Trance makes assassins very difficult to hit (as if they were hasted) and they take 1/2? damage. Lasts about 5-6 hours and can be used once every 24 hours.
These edges are unlocked at ~90% martial trance which probably takes awhile to get using it once per day.
Buki Edges: Only one can be chosen from this Buki Edge Set.
Kage Buki (Shadow Weapon) - Chance to evade area attacks while in Martial Trance.
Koumori Buki (Bat Weapon) - Immunity to blindness while in Martial Trance.
Kuma Buki (Bear Weapon) - Phenominal endurance while in Martial Trance. [+300 hp while tranced, soeffectively ~600hp more damage can be taken!!]
Kyojin Buki (Giant Weapon) - Titanic strength while in Martial Trance.
Orochi Buki (Serpent Weapon) - Higher frequency of strikes while in Martial Trance. [still a max of 4 attacks, just more likely to get them all]
Raion Buki (Lion Weapon) - +10 damage on attacks while in Martial Trance.
Sensei Buki (Master Weapon) - Skill with all weapons kinds while in Martial Trance.
Zo Buki (Elephant Weapon) - Immunity to knock out or paralyzing attempts while in Martial Trance.