On the wall of a sunless room next to the indoor garden where the men played, hung a painting by Max Liebermann, "Two Riders on the Beach," depicting two men riding horses across the wet sand, recalled Mr. Toren, an 88-year-old retired American lawyer who lives in New York.
Now that painting is at the center of a major art world mystery, one of the first works identified in a cache of 1,400 pieces collected by a German dealer under the Nazis and revealed in Munich last week. Mr. Toren said he was one of the only living relatives of David Friedmann, who records say once owned the painting, and plans to file a claim for it. "Two Riders on the Beach" was one of a handful of works revealed by the German authorities last week at a news conference about the Munich collection.
"It's mine. Who else should get it?" Mr. Toren told The Wall Street Journal on Monday in a phone interview from his home on Manhattan's Upper East Side. "It's the only picture I remember from my uncle."
Mr. Friedmann, a well-to-do Jewish art collector, owned about 10 paintings that were targeted for seizure by the Nazis, including another Liebermann piece, "The Basket Weaver," and paintings by Camille Pissarro and Henri Rousseau, according to a letter from the Gestapo that Mr. Toren said he has.
The Liebermann piece was missing for three-quarters of a century. Last week, Mr. Toren received a call from a lawyer in Berlin, Lothar Fremy, who had investigated the Friedmann collection in the past. He told Mr. Toren that the work was one of the pieces found in the garbage-strewn residence connected to Cornelius Gurlitt, the elderly son of an art dealer for the Nazis, Hildebrand Gurlitt. "I'm very excited after all these years," Mr. Toren said.
The work has been registered with the lostart.de database for several years, but the site hadn't previously confirmed that government officials had possession of the work, according to Jörg Rosbach, another lawyer who represents the family of Mr. Friedmann.
Mr. Toren said he escaped to Sweden with other children in a kindertransport rescue at age 14, a week before the war broke out in 1939. He said both his parents died at Auschwitz.
Should he convince German authorities that his family is the rightful owner of the Liebermann, Mr. Toren still won't be able to see it. He went completely blind six years ago over the course of three days after contracting shingles, he said.
He can still picture Mr. Friedmann's home—"the whole house was like a museum," he said—and described a trove of paintings, porcelain, pottery, Persian rugs and antique furniture.
Mr. Toren learned to ride horses on his great uncle's 10,000 acres of land about an hour from Breslau in the province of Silesia. Mr. Friedmann made his fortune as a landowner, leasing acreage for farmers to grow sugar beets. The property included a sugar factory, a distillery and a hunting lodge, Mr. Toren said.
Mr. Friedmann, who died peacefully in his sleep in the early 1940s, had a daughter who committed suicide after being briefly imprisoned by the Nazis, Mr. Toren said.
The art collector used to assemble a lively three-person card game called skat in his home every couple of weeks whose participants included the composer Richard Strauss, Mr. Toren said. He recalled walking 20 minutes or taking a short tram ride to get to his great uncle's villa, which he said was still standing in a town that became part of Poland after the war and is now called Wroclaw.
Mr. Toren moved to New York City in 1955 after a stint in the Israeli army and has stayed ever since. His wife, Sarah Brown, is 90 years old and lives with him. The couple has one son, who is also a lawyer.
The future of "Two Riders on the Beach" and any other possible works belonging to Mr. Friedmann that could be part of the newly uncovered art stash is still unclear. Mr. Toren said he had no interest in holding onto his great uncle's collection should it be returned to him and his brother, who is 92 years old and living in London. He would prefer to hand over "Two Riders on the Beach" to Sotheby's or Christie's, though he has few ideas about what he would do with the proceeds from any potential auction. "I don't like to spend money before I have it," he says.
Mr. Toren's life took another epic turn in 2001. He was heading to work at the World Trade Center, where he worked at a law firm formerly known as Brown & Wood, when his wife called and said the building had been hit by a plane. He turned around and went home.