Japan Atomic Energy Agency (JAEA) initiated R&D for nuclear forensics in 2011, responding to the Japanese national statement at Nuclear Security Summit in 2010. We have developed the basic analytical techniques required for nuclear forensics (isotopic composition analysis, impurity analysis, particle analysis, age-dating, prototype nuclear forensics library) and made efforts to sophistication of these technology as well. Through participating the 4th ITWG Collaborative material exercises, we could test our analytical techniques on real material of the fuel pellet and the crushed pellet. We have collaborated with U.S. Department of Energy and EURATOM in technical development and in information exchange for nuclear forensics. In order to identify issues to build corresponding system for nuclear forensics event, we have investigated foreign activities for capacity building against nuclear forensics event.