The leader of South Ossetia, Leonid Tibilov, has said he plans to hold a referendum like the one in Crimea in 2014 on whether to request annexation by Russia.

But even without a referendum, the nominally independent country is already Russian territory in all but name. It has its own small security force, but its self-declared frontiers are mainly guarded by Russia’s border service, an arm of the Federal Security Service, the post-Soviet version of the K.G.B. It houses three Russian military bases with several thousand troops and, with no economy beyond a few farms, depends almost entirely on Russian aid for its survival.

The green border signs that first appeared last year and now keep popping up along the zigzagging boundary warn that “passage is forbidden” across what is declared to be a “state border.” Which state is not specified, though locals are in no doubt about its identity.

“Russia starts right here,” said Mr. Tatiashvili, pointing to the freshly dug track that separates his house from Georgian-held land.

“But who knows where Russia will start tomorrow or the next day,” he said. “If they keep moving the line, we will one day all be living in a Russian-Georgian Federation.”

One of the new signs — written in English and Georgian — is just a few hundred yards from Georgia’s main east-west highway, and it puts a short part of an oil pipeline from Azerbaijan to a Georgian port on the Black Sea within territory controlled by Russia.

So tangled is the dispute over what land belongs to which side that each has its own definition of the line. Russia and South Ossetia insist that it is a border like any other — Venezuela, Nicaragua and Nauru also recognize it — while Georgia calls it “the occupation line.” The European Union, which has around 200 monitors in Georgia to keep tabs on the agreement that ended the 2008 Russian-Georgian war, also says there is no actual border, only an “administrative boundary line.”