Russians return to Vietnam with strong ties but weaker finances.(Knight Ridder Newspapers)

HANOI _ Savvy foreigners in Vietnam bark "Lien Xo!" to ward off pesky postcard sellers. It works like a charm because everybody here knows, even the teenage street peddlers, that the "Lien Xo" _ the Soviets_don't have any money. Not even enough for postcards

The impoverished Soviets may be long gone, but the Russians were back in force this week as president Vladimir Putin came to Hanoi Wednesday to forgive some old debts, sell some new weapons and generally try to rebuild a relationship that for the last decade has been colder than a Siberian winter

"It would be a stupid and unforgivable idea to lose the potential and the high level of the relationship which existed between our two countries," Putin said Thursday after signing bilateral accords on trade, technology and strategic cooperation.

Putin's 48-hour stop in Hanoi _ which comes after a visit to South Korea _ is the first ever by a Soviet or Russian head of state despite 50 years of diplomatic relations. At one time, the Soviet Union had been Hanoi's principal benefactor during the Vietnam War, but the relationship soured when virtually every ruble of assistance evaporated with the breakup of the Soviet Union.

But Official Hanoi has thrown its best diplomatic welcome at Putin, complete with motorcades and honor guards, gooey articles in the state-run press, red carpets, military bands and an invitation-only concert at the Opera House.

Former president Bill Clinton, who visited Hanoi and Ho Chi Minh City in November, was received a bit more stiffly, a bit more formally by the government. But Clinton drew large crowds of everyday citizens around his public appearances, an affection and fascination that has not been not reciprocated for the Russian president

Putin's official host is president Tran Duc Luong, who, like many Vietnamese officials of a certain age and rank, was educated in Moscow. He spoke Russian with Putin as the men waited to sign formal documents before a joint press conference Thursday.