My first DMB horse, as best as I can recall, was Prince Thou Art in 1975. DMB is shorthand for Derby Must Bet--a horse you feel compelled to play in the Kentucky Derby--not because he's the best horse, or even the favorite, but a horse who has a good chance, may have been overlooked, and is someone you've been following for so long that you'd flagellate yourself if he happened to win. DMB is only half of the acronym. In toto, it's DMBNMW--Derby Must Bet No Matter What. You don't get a DMB every year. Just enough to keep you in sackcloth and ashes.

Prince Thou Art had won the Florida Derby, but on paper, where the race is never run, there were too many reasons not to play him. In the Blue Grass, nine days before, he was a well-beaten third. He had lost eight of 11 starts, and ran from out of the weeds, a late-moving style that's problematical in a large Derby field. But he was owned by Darby Dan Farm's John Galbreath, who had already won the Derby twice. I knew the Galbreath family well, which is the wrong reason to like a horse, but que sera sera. Prince Thou Art's jockey, Braulio Baeza, was a big-money rider who had already won a Derby.

I thought I would get more than almost 3-1. But the 1975 Derby was considered Foolish Pleasure's to lose. There was scant respect for his rivals--Avatar, the Santa Anita Derby winner, looked overmatched in the Blue Grass; all Master Derby did was win, but for many he was an afterthought.

As the field turned for home, Chic Anderson, the announcer, shouted: "Here comes Prince Thou Art!" In the press box, I had my glasses on the Galbreath colt, and he was shortening stride and starting to hang. I wondered who Anderson was talking about. Oh, that would be Foolish Pleasure, who also emerged from back in the pack to win as he pleased. A week later, the New York Times interviewed Anderson about his classic gaffe. He manned up and took his beating. "Prince Thou Ain't," a clever headline writer wrote.

I should have sworn off DMBs on the spot. But the more you study any Derby, the more a DMB is likely to grab you by the lapels. Five years later, it was Jaklin Klugman. All he had to beat was a false favorite (Rockhill Native) and a filly (Genuine Risk) whose trainer didn't want to be there. The Hollywood ownership angle, no matter that it was misspelled, would surely have the complete blessing of those Derby gods. But Jack Klugman's colt finished third. It turned out that the filly was the real DMB in the race.

I don't have the stomach for much more of this. There was Cat Thief in 1999. Winless as a 3-year-old but seemingly a colt with no quit in him, his Derby-savvy trainer, Wayne Lukas, would find a way to get him home, and he would pay a lip-smacking 7-1. Mr. Derby Savvy won, all right, but with the 31-1 Charismatic. By the time Cat Thief won the Breeders' Cup Classic in the fall (his odds were up to 19-1 by then), I had long abandoned him. Love affairs with DMBs are short-lived.

About the only DMB I like to talk about is Spend a Buck in 1985. This was a Derby we'll probably never see again. A small field. No jockey willing to cook his horse early. A cocksure Angel Cordero in the saddle. It all came together, at 4-1. But there was a price to be paid. Except for Real Quiet, in 1998, I haven't gone to the bank with a DMB since then.

Now, this year. I keep looking for a fortune cookie that tells me to give up DMBs forever. But wouldn't you know? There are two DMBs, and they're in the same prep race, the Santa Anita Derby. One is Silver Medallion. Surely he's a synthetic-track horse, a grass horse, but if he wins on dirt in the Santa Anita Derby, he may cost me a lot of money in Louisville.

The other DMB is Anthony's Cross. Trained by a former Bob Baffert aide (Eoin Harty). Owned by Lynne de Kwiatkowski, who was there the day her father bought the future Horse of the Year, Conquistador Cielo, out of a sales ring. Already fully tested over the Churchill Downs racing strip. Anthony's Cross' job is easier now that Premier Pegasus isn't running, but I get the feeling that he will punch his ticket to Churchill Downs even if he doesn't win the Santa Anita Derby. So on May 7, the DMB will once more rear its ugly head. I can see it coming, a month off and a mile and a quarter away.