Short fields are rare in Hong Kong racing, but Sunday’s Group 3, $370,000 Queen Mother Memorial Cup Handicap at Sha Tin lured only five entrants.   There’s a reason for the lack of interest: The Queen Mother Memorial is run over 2,400-meters, about 1 1/2 miles, and there just aren’t true many 1 1/2-mile horses in Hong Kong.   Senor Toba might be one of them. Senor Toba exits Hong Kong’s 4-year-old classic series having finished a fast-closing fifth in the 1,800-meter Hong Kong Classic Cup and an even better fourth going 2,000 meters in the Hong Kong Derby. Senor Toba, trained by Caspar Fownes since being exported from Australia, raced once over this distance before coming to Hong Kong, finishing second of 18 in the Group 1 Queensland Derby.   :: Hong Kong: Free PPs, picks, analysis, replays, and live streaming The jump out of age-restricted races can overwhelm a Hong Kong 4-year-old, but the Queen Mother is a handicap and Fownes rightly points out the form of the Hong Kong Derby already shines. The race’s winner, Romantic Warrior, came back to beat older rivals in the Group 1 Queen Elizabeth II Cup; Hong Kong Derby runner-up California Spangle finished a creditable second behind the great Golden Sixty racing on the same card.   Senor Toba carries 120 pounds, including jockey Joao Moreira, and breaks from post 1. He gets 13 pounds from Butterfield, who will struggle to win under this impost, and gives between two and seven pounds to the three other starters.  One of those, Enjoying (118 pounds), looks like controlling speed, but he’s up in class from Class 2 handicap competition and has yet to race beyond 2,000 meters in three Hong Kong seasons.  First post for this 12-race card is 12:30 a.m. Eastern. You can catch all the action at DRFBets.com.