Masamune were swords created by Goro Nyudo Masamune (Priest Goro Masamune), a swordsmith of the late 13th and early 14th century, and is best regarded as Japan's greatest swordsmith. His swords were known for beauty and quality, said to have mastered forging techniques allowing for incredible durability through layering iron in such a way that its finished composition would be tensile enough to endure both heavy blows and a double forge-quenching sequence to reinforce such a quality to the point they were nearly impossible to dent normally, and naturally gave them surface activities that not just signaled such properties, but gave his swords amazing finishes, akin to stars under the night sky and power itself manifested surging like wild energy. Praised throughout the centuries since, Masamune's works would also become representative of katana with a pure, hallowed, and protective spirit, and are considered by most to be the ultimate definition of the katana, and the quality that all makers of katana wish to achieve.
正宗 / マサムネ [masamune] in Japanese. Uses the first spelling when not otherwise noted.
Final Fantasy I
Stats: ATK +56, ACC +50
Equip: ?
Obtain: ?
Description: A legendary katana without peer
Final Fantasy II

Stats: ATK +150, ACC +90%, EVA +4%
Equip: all
Obtain: ?
Description: A katana of unequaled power
Final Fantasy III

Stats: ATK 132, ACC 70, AGI +10, weight 1, Dark damage
Use: ONK, DRK, NIN
Treasure: Eureka (guarded by Kunoichi)
Type: Katana
Other: マサムネ in Japanese
Final Fantasy IV
Stats: ATK 60, ACC 120, STR +1, SPD +3
Equip: Edge
Buy: - (sell: 30,000 gil)
Treasure: Lunar Subterrane B8
Other: casts Haste when used in battle
Final Fantasy V
Stats: ATK +104
Equip: Samurai
Buy: - (sell: 5 gil)
Obtain: Kuza Castle (must one one of the tablets)
Other: always strikes first, can be equipped with two hands
Final Fantasy VI
Stats: ATK 162
Equip: Cyan
Obtain: ?
Description: Masterfully made katana
Other: Can be used with Bushido
Final Fantasy VII

Stats: ATK 99, Hit 255%, Critical +255%
Slots: 2+2+2, Growth: None
Equip: Sephiroth
Buy: - (Sell: -)
Obtain: while Sephiroth is in party in flashback
Other: can't be used with Throw
Final Fantasy IX
Stats: ATK 62, MAG +2
Equip: Zidane
Abilities: Sacrifice
Buy: - (sell: 6,500 gil)
Synthesize: Zorlin Shape, Orichalcon, 16,000 gil (Black Mage Village Black Cat synthesis shop (disc 4))
Steal: Marilith
Description: Sword from a foreign land
Type: Thief Sword
Other: inflicts Doom with Soul Blade
Other: マサムネ in Japanese

Final Fantasy XII
Stats: ATK 93, EVA 5
Range: 1, Charge time: 29, Combo chance: 40, Knockback chance: 0
Buy: - (sell: 0 gil)
A New Empire

Stats: (unknown)
Obtain: ?
Description: A relic from a faraway land, this sword sometimes inflicts massive damage against an uninjured foe
Type: Weapon
Final Fantasy Tactics
Stats: ATK 18, Parry 15% (when available)
Range: horizontal 1, vertical up 2, vertical down 3
Equip (job): Samurai, Onion Knight
Equip (character): Sword Saint
Equip (enemy): level 95 (Throw only)
Buy: - (sell: 5 gil)
Obtain: steal from a samurai in battle 2 of Lionel's New Liege Lord quest, Sticky Fingers an enemy, Rendezvous Mode multiplayer
Description: This katana's sheath is inlaid with beautiful patterns. It is the life's work of a master swordsmith.
Other: can be equipped on other jobs with the ability Equip Katana
Other: can be used with Dual Wield, Doublehand and Throw
Crystal Chronicles
Stats: STR +5
Treasure: Kilanda dungeon-end reward
Other: an Artifact
Ring of Fates
Stats: ATK 160
Buy: - (sell: 3,350 gil)
Craft: Foreign Weapon scroll
Bonus 1-star: ATK Boost 1, SP Boost 1
Bonus 2-star: ATK/SP Boost 2+Samurai Lore 2, ATK/SP Boost 2+Fast Charge 2, ATK/SP Boost 2+Tribal Secrets 2
Bonus 3-star: ATK/SP Boost 3+Samurai Lore 3+Fast Charge 3, ATK/SP Boost 3+Samurai Lore 3+Tribal Secrets 3, ATK/SP Boost 3+Fast Charge 3+Tribal Secrets 3, ATK Boost 4+Samurai Lore 3
All the Bravest
Stats: ATK+10, Number: P23, From: FF10
Equip: Samurai, Ninja, Auron
Drop: YAT-97
Description: Beautiful and deadly, this blade is rumored to belong to the great fencer Mi'ihen.
Pictlogica

Stats (lv1): STR +110, LCK +15
Stats (lv25): STR +165, LCK +35
Buy: - (sell: ? gil)
Obtain: limited-time initial equipment on Sephiroth
Type: Katana, Rarity: ★★★★★, Element: -
Other: can only be equipped by Sephiroth
Record Keeper

Masamune (II)
Stats: ATK +88, ACC 95 (lv1), ? (lv5), ? (lv10), ? (lv15), ? (lv20), ? (lv25), ATK +140, ACC 95 (lv30)
Max Level: lv20 (initial), lv25 (first evolve), lv30 (second evolve)
Type: Sword, Rarity: ★★★★★
Other: enables use of the Lord of Arms Soul Break when equipped by Firion

Masamune (VII)
Stats: ATK +80, ACC 95 (lv1), ? (lv5), ? (lv10), ? (lv15), ? (lv20), ? (lv25), ATK +132, ACC 95 (lv30)
Max Level: 20 (initial), 25 (first evolve), 30 (second evolve)
Type: Katana, Rarity: ★★★★★
Other: adds the Hell's Gate Limit Break when equipped by Sephiroth
Category: Equipment