Japan’s importance to the world’s pharmaceutical drug marketplace is attributable to two simple facts. First, its irresistible size as the world’s second largest pharmaceutical market (1). Second, Japanese pharmaceutical research and development (R&D) has a proven track record of success in the American pharmaceutical market (2,3). Therefore, it is important to understand Japanese patenting issues so that companies can make informed decisions when seeking to patent or commercialize their pharmaceutical and drug delivery inventions in Japan.