Banknotes from Japan and around the world are the main theme of this free museum run by the National Printing Bureau. Watermarks, holograms, color-shifting inks, microprinting and textural effects - these are some of the many anti-counterfeiting measures used when printing banknotes, and they're all explored here in detail, including in hands-on exhibits that let you examine and test real banknotes.
Other sections of the two-story museum are devoted to historical Japanese banknotes, unusual and rare banknotes from around the world, plate-making technology, and printing inks. Although there's a smaller section devoted to postage stamps - another responsibility of the National Printing Bureau - diehard stamp enthusiasts will probably find more of interest (including more than 350,000 stamps) at the Postal Museum across town in Tokyo Skytree.
Sitting in its own display area on the ground floor is one of the world's few surviving Stanhope printers, a manual letterpress printer dating from the early 1800s which has been recognized as a national important cultural asset. And if you want to test your strength, there's a shrink-wrapped package containing 100 million yen in ten-thousand-yen bills which you can lift to see how heavy it is.
Admission to the museum is free, and photography is allowed everywhere except for a couple of sensitive areas. Most captioning is in Japanese only, but there's an illustrated eight-page English-language brochure that explains everything in thorough detail.