It has been nine years since Ivan Allan last brought a horse from Singapore to the Washington, D.C. International, but he still is haunted by the memory.

"When I came here with Jumbo Jet," the trainer said, "I was overwrought about the whole thing. (Jockey) Lester Piggott told me, 'This horse can win,' and as I saw my horse work, and the other horses work, I started getting excited. That didn't last long.

"Jumbo Jet had been 10 or 15 lengths behind, but he moved up within about three lengths of the leaders, and he was a horse with a tremendous finish. I saw him flick his ears as Lester creeped up on the inside, and I said, 'Terrific!' Then I saw a horse go down and something go over him."

The horse who fell on that soggy turf was Boreen, and the horse who fell over him was Jumbo Jet. Afterward, Piggott would tell Allan, "We were just cantering; we were going to win it," but that was small consolation. Jumbo Jet survived the spill, but he never was the same animal who had become virtually a national hero in Singapore.

"Since then," Allan said, "I've been determined to get a horse good enough to come back here." He has returned to Laurel Race Course with a horse named Siapa Rajah III, who he hopes will atone for the greatest disappointment of his training career.

It has been a career marred by few disappointments. Allan was a law student at Singapore University when his father, a trainer, died suddenly, and he took over the stable. He has won virtually every major race on the Singapore-Malaysia circuit, and has been the leading trainer there for the past five years. Not only that, but one of the racing papers in Singapore noted that "Allan . . . shows that gambling can pay. A self-made man, he apparently owes his entire wealth to winnings from betting."

In pursuit of an International-quality horse, Allan went to New Zealand last year and negotiated the purchase of Siapa Rajah. The horse's name means "Who is king?" but it is his owner's name that really requires translation. Allan bought the animal for Datuk and Datin Amar Wee Hood Teck.

(Datuk and Datin are titles like Lord and Lady. Amar is a rank like colonel. Wee is the last name. Hood and Teck are his first and second names. Wee's resume notes that he is an industrialist who is chairman of 18 different companies and drives a Rolls-Royce, a Ferrari, a Daimler, a BMW and a Mercedes-Benz).

While he was competing in New Zealand, Siapa Rajah was good enough to defeat Caterman, who subsequently came to this country and won the rich Hollywood Gold Cup. And when Siapa Rajah III raced against the relatively weak competition in Singapore, he elicited comparisons with the legendary Jumbo Jet as he won major stakes under as much as 137 pounds.

Allan recognizes that winning the Perak Derby and the Tunku Gold Cup is a far cry from winning the International; he also knows it is not easy for a horse to overcome the effects of a 48-hour journey. But after his 1972 experience he believes that a Singapore horse might conceivably be good enough to win at Laurel. All he asks this year is a fair chance to prove that thesis