This paper describes changes which took place in 37 Hong Kong primary schools where class sizes were reduced from 38 to between 20 and 25. Chinese, English and mathematics classes were observed over three years from Primary 1 (aged 6) to Primary 3. For 75% of observations no child was the focus of the teacher's attention in large classes. Reducing the class size did not change this situation appreciably, although teachers claimed that smaller classes increased the amount of individual attention that pupils received. For some teachers cluster analysis did identify shifts in teaching methods away from whole class instruction and the implications of this finding for when Hong Kong "goes to scale" across the primary phase are discussed. (Contains 7 tables.)