One of the swords, which possessed a Kamakura blade from the 13th century, was the last conventional katana to appear at a public auction (as of this writing). It was acquired for $418,000 by a European buyer, making it the most expensive Japanese sword in the world. But that's simply from the market. If you were to go to the source, then this sword might cost you more than that. According to some reports, the real price of this sword is much higher. So high that no one knows exactly. Some say it's worth millions, others say it's not even worth the cost of production. Either way, it's a lot of money. In fact, it's so expensive that nobody can actually buy it. It's owned by a museum and on display only during certain exhibitions. Even then, you need a special ticket to see it. The current owner did sell another similar sword at auction recently. This one had a longer blade and was called a "daishō". It sold for $500,000, so there are people who are willing to pay big money for old swords from Japan! Another famous katana is the one used by Miyamoto Musashi. The price tag on this sword is estimated to be around $1 million.