Doesn't appear to be listed on the US site
The UK commercial is billing the first episode as a programme about the Japanese swordsmith, here's the blurb on the UK site
Master Swordsmith of Imperial Japan
To be a master swordsmith in 13th-century Japan was to hold a position of exceptional respect and authority. Masamune was the supreme practitioner in this, the golden age of the sword. In the face of Mongol invasions the Emperor's rule had broken down.
Great power was held by the Samurai, mercenary warriors who enjoyed high social status and wealth in return for their military service. Famed for their fighting skills, bravery and loyalty, the Samurai followed an ancient code of honour that permeates Japanese society to this day.
"The way of the sword" - the ancient art of Iaido - was crucial to the Samurai. Iaido focuses on the expert use of the Katana (curved sword) and the discipline of mind and body.
Remarkably light and easy to handle, the Katana was an extremely sharp, strong and durable weapon. In the hands of a Samurai they were lethal. The Katana is still a central part of Japanese culture.
In Japan's creation myth the Empress Sun God hands her grandson a sword as he descends to rule on earth. The sword was an extension of the warrior's soul. Thus the smiths who crafted these weapons were venerated as priests. Masamune was Japan's greatest ever swordsmith, his most prolific period coming at the time of the Second Mongol invasion in 1281. The Katanas he crafted had mythical and spiritual qualities, and a single blade could take up to 90 days to forge.