Masamune is a legendary swordsmith from Japan who lived during the 13th century. While there are many legends and stories surrounding Masamune and his swords, it is difficult to confirm the authenticity of specific swords attributed to him. The majority of swords attributed to Masamune are either lost to time or the subject of debate and speculation.

However, there are several swords that are believed to have been made by the Masamune school, which refers to a group of swordsmiths who followed Masamune's style and techniques. These swords are highly regarded for their craftsmanship and artistic beauty. Some of these swords are designated as National Treasures or Important Cultural Properties in Japan and are carefully preserved in museums, shrines, or private collections.

It's important to note that the identification and authentication of ancient swords, especially those attributed to specific legendary swordsmiths, can be challenging. Many swords undergo alterations, damage, or changes in ownership over time, making it difficult to establish a direct lineage or provenance. Additionally, the demand and market for Masamune swords have led to forgeries and misattributions over the centuries.

If you have a specific sword you believe to be connected to Masamune or the Masamune school, it is advisable to consult with experts, historians, or professional appraisers who specialize in Japanese swords to obtain a more accurate assessment of its authenticity and historical significance.