Gunbai
The uchiwa gunbai was a war fan carried by high-ranking military leaders and generals during battle to communicate commands on battlefield. However since they were made from tougher materials like iron or hardwood they could withstand the blows of swords and arrows and were actually used as a weapon as well. One of known user of gunbai was Takeda Shingen, whom used it to fight in the fourth battle of Kawanakajima against daimyo Uesugi Kenshin. As he did not have time to grab a sword, he used his gunbai to fend off the enemy forcing him to retreat. Supposedly he managed to land number of blows with it.
Many of them were decorated with family crests as well as dragons, sun, moon and constellations, sanskrit characters and quotations from Sun Tzu's 'the Art of War.' Also they are still used in present day in sumo wrestling by referees.
source: Berlin Samurai museum
