which actor was casted for it?
Ken Watanabe.
Date Masamune
He was played by Ken Watanabe in the popular 1987 NHK series "Dokuganryū Masamune".
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".
wiki:12142089
Date Masamune [SEP] Introduction
As a legendary warrior and leader, Masamune is a character in a number of Japanese period dramas. He was played by Ken Watanabe in the popular 1987 NHK series "Dokuganryū Masamune".