The deal is the first that Symbian has announced since it was created last summer through Psion injecting its EPOC operating system software into a joint venture with mobile phone manufacturers Motorola, Ericsson and Nokia.
Symbian and NTT DoCoMo said the alliance would define specifications to provide complete end-to-end solutions for the Japanese market. The partnership is expected to develop network solutions and services as well as hand-held communication devices.
The deal is a breakthrough for Symbian, which has come in for intense criticism recently for failing to sign up new licensees for EPOC. Japan is expected to be a key market.
Shares in Psion, which has a 33 per cent shareholding in Symbian, closed up 105p for 860p.