http://www.historyinternational.com/index.html
and type in "Masamune" in the search section.
There will be two showings, Monday the 29th 9 to 10 p.m. and (about four hours later) Tuesday early morning 1 to 2 a.m. (Pacific time, check your local listing) I'm sorry I couldn't give more notice but I just found it a few minutes ago.
This is a premium channel on Dish network (Check listings for History Channel International "Almanac") and is NOT the same as the History Channel. It might be on cable.
