They stood for a while in front of the building, brandishing baseball bats 'as if they wanted to do something', said Mr Lapiner. Then the police arrived and the thugs drove away.
This did not take place in a ghetto in Eastern Europe in the 1930s, but in central Tokyo two months ago. It had happened several times before: usually on Hitler's birthday.
The Jewish Centre has a synagogue, a kindergarten, some offices and a bagel bakery. 'They were saying something about the Jewish conspiracy to take over the world,' said Mr Lapiner. 'After leaving us, they drove on to the Israeli Embassy.'
Japan does not seem an obvious breeding ground for anti- Semitism: there are at most 2,000 Jews living in the country, and few Japanese would be able to distinguish them from other Westerners in their midst. But although there have not yet been any physical attacks on Jews in Japan, several Jewish friends have spoken nervously about anti-Semitic demonstrations by extreme nationalists, and the appearance of a spate of anti-Semitic books blaming a Jewish conspiracy for Japan's recession.
Last week an advertisement for four anti-Semitic books appeared prominently in Yomiuri, the largest daily newspaper in Japan. Some of the books verge on the absurd: one, Rockefeller versus Rothschild, purports to explain how Zionists and big American capitalists are competing to destroy Japan, and how Jews plotted the Tiananmen Square massacre. But the fact they were advertised in a mainstream newspaper was enough to make the local rabbi, James Lebeau, send out cautionary notes to his community.
Japan has harboured theories of its racial homogeneity and uniqueness for generations, and xenophobia rides high at many levels of society. Anyone who is in some way different can face racial prejudice in this highly self-aware and inward-looking society.
With their small numbers, it is not the physical presence of Jews that incites extremists. Most of the anti-Semitic material published deals with a fuzzy notion of international Jewish financial power, not with the Jews living in Japan. It is a strange form of anti-Semitism. In some ways the Japanese look up to the supposed power of the Jewish 'financial clique'.
Some of the books simply promise to make the reader rich 'by buying the same stocks as Jews buy'.
Other publications which are freely available are more sensational.
Lucifer's Last Conspiracy, by Izumi Koishi, explains how half of humanity will be killed by 1999 and the Japanese will be made into slaves. The Rothschild Family: The Devil's Canon of the World Financial Clique, by Akira Kagami, continues the diatribe against the Rothschild family and its designs on Japan. The Jews are sneaking into Japan - what are the plans of those terrifying devils?, by Ushiyama Kaichi, begins with 'proof' that the Holocaust never happened, and then proceeds to lay out how Japan has been forced to resist Jewish domination for 2,000 years.
'The Jews serve as a rallying-point for Japanese nationalists' fears of foreigners,' said Mark Schreiber, a writer who has been keeping a record of anti-Semitic publications in Japan. He concedes that many of the anti-Semitic conspiracy theories are concocted to make money, and are made to sound sensational. But, he says: 'If enough of this hate material is generated, some of these people will snap.'
There are no laws against publishing or promoting overtly racist material in Japan, but the government is occasionally embarrassed into taking some action.
Last year Yoshiji Nogami, a Foreign Ministry official, wrote an article for Yomiuri criticising the anti-Jewish publications. He wrote: 'The open sales -and reading - of prejudice-filled low-brow anti- Jewish publications testify to the ignorance of the Japanese people. It is a disgrace.'