Fun Trivia : Did you know that Osaka Castle was black?
It was built by the real Taiko, Toyotomi Hideyoshi, before it was destroyed and reconstructed into a white castle by Tokugawa Ieyasu. After the death of the "dictator" Oda Nobunaga, Hideyoshi constructed impressive castles like Osaka to herald his new position.
Castles that were built during Hideyoshi's reign like Hiroshima, Okayama and Matsumoto are black. Castles built during Tokugawa's reign like Hikone, Himeji and Nagoya are white. So when you see a castle on your next trip to Japan, you can guess who built it. 😉
The differences in color is due to the resources availability at the time, as white plastering were more expensive than black lacquered timber, so it is of no surprise that Tokugawa later used white for his castles as a symbol of wealth and power.
You can read more from the book, Samurai Castles by Jennifer Mitchelhill which share the history of Japanese castles, from its designs, architectures, layouts, significance and legends, coupled with wonderful photos of the castles by David Green.