As a child, Peterson also studied with Hungarian-born pianist Paul de Marky, a student of István Thomán, who was himself a pupil of Franz Liszt, so his training was predominantly based on classical piano. Meanwhile, he was captivated by traditional jazz and learned several ragtime pieces and especially the boogie-woogie. At that time Peterson was called "the Brown Bomber of the Boogie-Woogie".
At the age of nine Peterson played piano with control that impressed professional musicians. For many years his piano studies included four to six hours of practice daily. Only in his later years did he decrease his daily practice to just one or two hours. In 1940, at fourteen years of age, Peterson won the national music competition organized by the Canadian Broadcasting Corporation. After that victory, he dropped out of school and became a professional pianist working for a weekly radio show, and playing at hotels and music halls.
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Oscar Petersen performing Hymn to Freedom