Children usually entered primary school at seven years of age for six days a week, which after regulatory changes in 1995 and 1997 were changed to five and a half and five days, respectively. The two-semester school year consisted of 9.5 months, and began on 1 September and 1 March, with a summer vacation in July and August and a winter vacation in January and February. Urban primary schools typically divided the school week into twenty-four to twenty-seven classes of forty-five minutes each, but in the rural areas, the norm was half-day schooling, more flexible schedules, and itinerant teachers. Most primary schools had a five-year course, except in such cities as Beijing and Shanghai, and later other major cities, which had reintroduced six-year primary schools and accepted children at six and one-half years rather than seven.