Magic marker in hand, Roy Williams used an overhead projector to explain the intricacies of Kansas University basketball to several hundred high school, junior college and small-college coaches on Saturday morning at Allen Fieldhouse.

Williams, KU’s 15th-year coach, was in his element, drawing X’s and O’s and plenty of arrows while diagramming plays for an attentive audience.

Talk of primary breaks and secondary breaks, switching out and press offenses and defenses dominated Williams’ annual coaching clinic chalk talk  with some generalities thrown in between.

“Run, run, run  I don’t mean jog or loaf like I run at lunch. At practice you’ll hear me yell that more than anything else,” Williams said of a vital practice message to his players.

“We’ve had 18 practices, and yesterday’s was about the only bad practice we’ve had (this preseason). I don’t know if it was after a day off or what, but mentally we were not into it as much. We do work extremely hard and every day.”

KU has been working as hard as ever this preseason. Depth after a strong starting five remains a major question mark heading into Monday’s exhibition opener against EA Sports All-Stars (7 p.m., Allen Fieldhouse).

“Set plays do not come into play that much. We have not yet talked about what set plays we’ll have. I have no idea of a set play we’re going to run yet,” said Williams, noting most of KU’s points came off the fastbreak or in freelance offense last season.

Williams stresses basics on offense and defense this time of year, and he likes what he’s seen defensively from his backcourt of Aaron Miles and Kirk Hinrich.

“Jerod (Haase) and Jacque (Vaughn) are the two best defensive guards I ever had,” he told the coaches on hand. “If in our scouting report our coaches said their (opponents) two guards did the most of the scoring, I started feeling better, because Jacque and Jerod were so good.

“We may have the best since Jacque and Jerod or close to it with Aaron and Kirk. Both are quick. Both are tough. Both have savvy. If the other team gets the most of their scoring out of their guards, it could be a heck of a match. Now, we’ve got to stay out of foul trouble. We’ll play more zone to stay out of foul trouble.”

Williams needs strong defense out of his post men, as well as guards. He said the Jayhawks prefer playing big men straight up, not doubling-down in the post.

“We did it (double) in the past a couple of times against Bryant Reeves,” Williams said of the former Oklahoma State 7-footer and former NBA player. “Bryant scored 31 points with 20 rebounds one time against us. That’s one time Greg Ostertag tried to play his defense instead of my defense. They came here and we gave Greg some help. Big Country had zero (points). I told our guys Randy Rutherford (OSU guard) couldn’t single-handedly beat us. Randy Rutherford only had 45, but we did win the game.”

Williams told the coaches they might consider mismatches on defense that look ridiculous on paper.

“We were playing St. John’s in the finals of the Preseason NIT in ’89 or ’90, and they had a little guard named Boo Harvey,” Williams related. “Boo was killing us. Kevin Pritchard couldn’t stop him, and Kevin was a great, great player and is a great coach.

“Jeff Gueldner couldn’t stop him. Ricky Calloway couldn’t stop Boo. I was searching. I took Terry Brown, 6-feet tall, and put Terry on Malik Sealy, who was 6-foot-7 and played in the NBA until two years ago.

“Terry was 6-foot if we stretched him. We put Terry on Malik, who was trying to post him up. Malik started yelling, ‘Boo, get the ball here.’ He wanted the mismatch.

“Boo passed to Malik, who shot over Terry and missed it. Malik yelled for it again, and darned if Terry doesn’t get around him and bat the pass. The third time, Boo threw it out of bounds. They had one missed shot, turned it over twice and the next time down court Boo is out of rhythm.

“He had one field goal the next 12 minutes of the game and we were able to win. So I really don’t worry about mismatches that much.”