Battles & Wars › Medieval wars › The sword
Japanese sword (tachi and katana)
curved tachi by c. 1000; katana from c. 1400s· Invention or discovery· Weapons, armor & warships
Mostly agreedGood evidence; some details, dates or numbers uncertain.
Curved, single-edged Japanese swords: first the long cavalry tachi, later the katana worn edge-up by samurai on foot.
See it on the Battles & Wars map →What happened
Smiths folded and hammered steel smelted from iron sand in clay furnaces (tatara), then coated the blade in clay, thicker on the back, before quenching. The thinly coated edge cooled fast and became very hard; the spine stayed softer to absorb shocks, and the uneven cooling helped form the curve. The long tachi, worn edge-down, suited mounted warriors by about 1000. From the 1400s, as fighting shifted to foot soldiers, the shorter katana, worn edge-up through the sash, took over.
Why it matters
It became the emblem of the samurai class, though bows, spears and later guns did more of the fighting. Its edge-hard, spine-soft design is a classic of metalworking.
How we know
Thousands of signed, often dated blades kept in shrines and collections, some designated National Treasures; Japanese war tales and smiths' traditions; and metallurgical studies of the steel.
Still debated
How much fighting was done with swords is debated: warriors' wound reports from the 1300s–1500s suggest arrows and later bullets caused most injuries.
Connections (4)
▸Japanese sword (tachi and katana) faced the Mongol invaders in the Mongol invasions of JapanMostly agreed
The connection
In 1274 and 1281 samurai met Mongol, Korean (Goryeo) and Chinese troops on Kyushu's shores. Their main weapons were the bow and the long tachi. The invaders fought in massed formations with exploding bombs, unlike samurai single combat. In 1281, Japanese night raids on the anchored fleets used swords at close quarters, before a typhoon wrecked much of the fleet.
When and how
Hakata Bay and Takashima island, Kyushu, 1274 and 1281; warriors of the Kamakura shogunate against Yuan and Goryeo forces.
How sure are we?
The Mongol Invasion Scrolls, made for the samurai Takezaki Suenaga, show tachi and bows in use; underwater finds at Takashima include weapons and bombs.
Debates and open questions
Later lore says the invasions pushed swordsmiths to make thicker, tougher blades; evidence for that change is thin and debated.
▸Japanese sword (tachi and katana) was confiscated from peasants by Toyotomi HideyoshiWell documented
The connection
In 1588 Hideyoshi, who had nearly reunified Japan, ordered the 'sword hunt' (katanagari): farmers and temples had to hand in swords, spears, bows and guns. The edict said such weapons encouraged revolts and promised to melt them into fittings for a great Buddha statue in Kyoto. The aim was to fix a line between armed samurai and unarmed farmers.
When and how
Japan, by edict in the seventh month of 1588; Toyotomi Hideyoshi, with regional lords enforcing it.
How we know
The edict's text survives along with local records of weapons collected, and a 1591 edict then froze movement between social classes.
Debates and open questions
How thoroughly it was enforced is debated; many villages kept some weapons, and some historians see status marking, not disarmament, as its main effect.
▸Japanese sword (tachi and katana) was overtaken on the battlefield by The gun: arquebus and musketMostly agreed
The connection
Even before guns, Japanese battles were fought mainly with bows and spears; the sword was a sidearm. After matchlocks arrived in 1543, Japan made them in large numbers, and by the 1570s massed gunners and spearmen dominated. The katana became more a mark of samurai status than a main weapon.
When and how
Japan, from 1543 (Tanegashima) through Nagashino (1575) and the Imjin War (1592–98).
How sure are we?
Warriors' wound reports, filed to claim rewards, show arrow and later gunshot wounds far outnumbering sword wounds.
Debates and open questions
How far Japan later 'gave up the gun' under the Tokugawa, as Noel Perrin argued, is disputed; guns stayed in use but production fell.
▸Masamune, Japan's most famous swordsmith perfected the steel of the Japanese sword (tachi and katana)Mostly agreed
The connection
Around 1300 Masamune made mostly tachi, long curved swords worn edge-down, and daggers. His blades combined a hard edge with a tough body and a vivid crystalline grain. Later owners shortened many of his tachi to katana length, and his style became the model later smiths aimed at.
When and how
Kamakura, Sagami province, Japan, about 1300; a later traditional list of his 'Ten Great Disciples' credits them with spreading the Sōshū style.
How sure are we?
Surviving attributed blades, several of them National Treasures, and later appraisal records connect his style to later katana.
Debates and open questions
'Perfected' is a later judgment: his methods are reconstructed from the blades, not written records, and attributions rest on connoisseurship.