The Celtics are the world champions and they can hardly be better than they were last year when they took a long early lead, held it for three months and then breezed past Minneapolis in four straight games for the title. This year's champions will be the team that can beat Philadelphia and Wilt Chamberlain, and the Celtics surely have the best chance in the East. They have balanced scoring power: up front they have Tom Heinsohn, an amazing shooter whose occasionally erratic temperament is the only thing that has kept him from true stardom, the rugged Jim Loscutoff and Bill Russell, who was the second-best percentage shooter in the NBA last season. In the backcourt they have Bill Sharman and the incomparable Bob Cousy, who have both averaged 18 points or better per game for many years. In reserve are two men who can play either the front or back court: the speedy Sam Jones and Frank Ramsey, the game's greatest sixth man. In the battle with Chamberlain, however, two other factors could swing the tide. First is the savvy of Coach Red Auerbach, whose explosive courtside behavior has long obscured the fact that he has one of the keenest minds in the game. And second, of course, is Cousy's brilliant generalship, which probes for rival weaknesses and exploits them relentlessly. None of which takes into account Russell's determination to maintain his rating as basketball's best defensive player. Gene Conley and K. C. Jones are vastly improved players, and three rookies, John Richter, Gene Guarilia and Maurice King, are all ready to play pro ball. King, a guard, has a tough job of breaking into a squad loaded with backcourt talent. Richter, battling for a corner spot, seems the best bet to stick past cutdown date.