The Optimal viewing position (OVP), the position where word recognition is the best, is biased to the left for English words. Several explanations have been proposed to account for this phenomenon, including the left hemispheric dominance for language, asymmetric information structure of words, and reading direction. However, it is unclear which factor(s) is necessary or sufficient to cause an asymmetric OVP. Using music reading, which shares only the reading direction but not the other two factors with word reading, we show that the OVP for three-note sequences is significantly biased to the left only for expert readers but not for novices. The degree of asymmetry in the OVP curve for music readers increases with individual reading skill, suggesting that their OVP is gradually shifted to the left during the development of reading skills. These suggest that habitual reading direction is sufficient to account for a biased OVP to the left.