what is his nationality?
Japan.
Ken Watanabe
He is the first Japanese actor to be nominated in this category. 
who is hasekura tsunenaga? He was a kirishitan Japanese samurai and retainer of Date Masamune. what  does the latter mean? As a legendary warrior and leader, Masamune is a character in a number of Japanese period dramas. any drama containing the role of the mentioned character? Yes,  NHK series "Dokuganryū Masamune". which actor was casted for it? Ken Watanabe.
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Ken Watanabe [SEP] Introduction
In 2014, he starred in the reboot "Godzilla" as Dr. Ishiro Serizawa, a role he reprised in the sequel, "". He lent his voice to the fourth and fifth installments of the "Transformers" franchise respectively, "" and "", as Decepticon turned Autobot Drift. He made his Broadway debut in April 2015 in Lincoln Center Theater's revival production of "The King and I" in the title role. In 2015, Watanabe received his first Tony Award nomination for Best Performance by a Leading Actor in a Musical at the 69th Tony Awards for his role as The King. He is the first Japanese actor to be nominated in this category.