What is the highest selling katana?

As a keen collector of traditional Japanese swords, I'm particularly fascinated by the katana, its elegance and prowess embodying the essence of samurai culture. But among the vast array of katanas that have been crafted over the centuries, I'm left wondering: What is the highest selling katana in history? Could it be the legendary Muramasa blades, whose sharp edges and intricate designs have captivated collectors worldwide? Or perhaps a modern masterpiece, crafted by a renowned smith using the latest techniques? I'm eager to delve deeper into this question and uncover the secrets behind the katana that has achieved such unprecedented popularity and sales.