Just days after a three-day visit to Japan by President Putin, a former KGB agent, Japan-Russian relations were put under a cloud with the arrest yesterday of a high-ranking Japanese naval officer on suspicion of selling defence secrets to a Russian spy.
In a double embarrassment for Japan, whose Self Defence Forces (SDF) have a reputation for porous security, police say the information passed on concerned the US as well as the 11,000-strong Japanese navy.
Lieut Cmdr Shigehiro Hagisaki (38) was arrested early yesterday morning after police interrupted a restaurant rendezvous with an attache at the Russian embassy in Tokyo, said a police spokesman. According to local media reports, the attache is a member of the Russian intelligence organisation, GSU.
Police refused to say precisely what type of information they think was being sold, but Japanese media commentators are speculating that it related to submarine capabilities and movements. Cmdr Hagisaki, who is a fluent Russian-speaker and expert on the Russian navy, previously served as a submarine captain.
The attache is claiming diplomatic immunity to evade police questioning. The Russian embassy refused to comment.
Police seized hundreds of documents from Cmdr Hagisaki's home and workplace in raids yesterday. He is alleged to have photocopied classified papers taken from the National Institute for Defence Studies for delivery to the attache.
The two men met at least 10 times over the past 12 months. Ironically, they first met at an SDF gathering aimed at promoting contacts between military personnel of other countries.
The government spokesman, Mr Hidenao Nakagawa, described the case as "very regrettable", but said the government would take no immediate action.
The spy scandal comes at a bad time for the two countries, which have technically been at war since August 1945. There had been hopes that a long-standing dispute between the two nations over four islands off north-east Hokkaido, which were seized by Russia in the final days of the second World War, could be resolved during Mr Putin's visit.
The issue is a major rallying cause for Japan's ultra-nationalists, who regular blast tirades from loudspeaker trucks outside Russia's embassy demanding the return of the southern Kurile islands.
However, there was no appreciable progress on the Kuriles question. The Prime Minister, Mr Yoshiro Mori, reiterated to Mr Putin on Monday Japan's position that a peace treaty won't be signed until the issue is sorted out. For Japan, resolution means a handover of all four islands. Mr Putin has his own more numerous nationalists to mollify and the countries made no real progress.
It seems likely that political considerations delayed the arrest of Mr Hagisaki until after the sensitive Putin-Mori talks on the Kuriles.