The Japan Patent Office (JPO) and the UK Intellectual Property Office (UKIPO) agreed to make permanent their Patent Prosecution Highway (PPH) scheme from 10th March 2010. This scheme, which had been piloted since 2007, allows businesses to benefit from faster patenting in the UK and Japan as the process becomes more streamlined. Once an applicant has received a favorable decision from one office, they can then request accelerated processing of corresponding patent applications filed in the other.
Japan also has permanent agreements with the US and Korea, whilst pilot schemes are continuing with the European Patent Office (EPO), Germany, Denmark, Finland, Russia, Austria, Hungary, Singapore, and Canada.
Source: The Ministry of Economy, Trade and Industry (Japan)