The state’s Division II high school boys basketball playoffs begin this week and it is clearly one of the most contested seasons ever in Tucson. Cholla is 22-1 overall and has won 18 straight. Sunnyside is 23-4, Cienega is 22-3, Sahuaro is 24-4 and Nogales is 22-6. They’re all ultimately trying to unseat defending state champion Phoenix Shadow Mountain, which is without star guard Michael Bibby, who is out with a knee injury. Wednesday’s doubleheader at Cholla High School — Cienega vs. Sahuaro and Sunnyside vs. Nogales — is virtually a state Final Four in itself.