I'm starting this thread for both museums that specialize in Arms & Armor and special exhibits of Arms & Armor at regular museums.
Here's links to some previous postings:
Arms and Armor at the Metropolitan Museum of Art
Lords of the Samurai at the the San Francisco Asian Art Museum
The Spirit of Budo: The History of Japan’s Martial Arts
Samurai: The Way of the Warrior at the Frist Center, Nashville TN
Samurai: Japanese Armor from the Ann and Gabriel Barbier-Mueller Collection
Evangelion and Japanese Swords at the Osaka Museum of History
Armi e potere (Arms and Power), Castel Sant'Angelo and Palazzo Venezia, Rome
RIP Higgins Armory Museum
My my, that's a lot of Japanese Arms & Armor special exhibits.
More to come...