His swords were famed for their exceptional beauty and quality even despite that in that period, metals for swords were very impure.
Though he is known to be the greatest swordsmith, his signed pieces are quite rare. Masamune swords are found to be made during Kamakura to Nanboku-cho era based on the designs and style of his works.
• Nanboku-cho Period
The years 1334-1393 was the Nanboku-cho period and rebellion and conflict between two emperors Godaiko (Go-Daigo of the Southern Court) and Ashikaga Takauji (Northern Court) were at hand. This had caused wars for more than 50 years and the demand for swords increased tremendously. Long swords were created suitable for on foot fights. The north court won the war.
• Muromachi Era
Muromachi Era (1394-1595) started out as a more peaceful period in the history of Japan and that was before the Onin-war was called out. In this age, the types or categories of the swords are divided into Early, Middle, and Late Muromachi groups. In the middle of Muromachi, the history of Katana started. It is in this era that katana swords were made for Samurai warriors. They were slightly curved swords shorter than the traditional tachi. Their cutting edge was facing upwards that made slashing of opponents easier.
• Edo Era
It was from 1596-1867 called the Edo Era that the swords of finer quality were made. With more accessible materials like steel and wood plus more developed and experienced Japanese sword makers, there was an obvious difference between the quality of the swords made during the earlier periods and those made in the Edo Era. The use of swords gained popularity that sword fighting schools were established.
In the later part of this period, firearms were introduced to Japan and a possible fall of the Japanese sword history dawned. Soon after, bringing swords became illegal that even the samurais’ rights to carry swords were taken from them. Consequently, the sword industry declined. In 1953 the making of swords was legalized again but the demand for them has never been regained.
Though the Japanese sword history has already passed its peak, the swordsmanship and Japanese sword making remains to be a mystical art. Countless people today, Japanese and non-Japanese alike, would still want to learn the ways of the old sword smiths. In addition, there are quite a huge number of people who are seriously engaged in Japanese sword collecting nowadays.