William James "Count" Basie (/ˈbeɪsi/; August 21, 1904 – April 26, 1984) was an American jazz pianist, organist, bandleader, and composer. In 1935, he formed the Count Basie Orchestra, and in 1936 took them to Chicago for a long engagement and their first recording. He led the group for almost 50 years, creating innovations like the use of two "split" tenor saxophones, emphasizing the rhythm section, riffing with a big band, using arrangers to broaden their sound, his minimalist piano style, and others.

Many musicians came to prominence under his direction, including the tenor saxophonists Lester Young and Herschel Evans, the guitarist Freddie Green, trumpeters Buck Clayton and Harry "Sweets" Edison, plunger trombonist Al Grey, and singers Jimmy Rushing, Helen Humes, Dennis Rowland, Thelma Carpenter, and Joe Williams.

As a composer, Basie is known for writing such jazz standards as "Blue and Sentimental", "Jumpin' at the Woodside" and "One O'Clock Jump".

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