Adopted by his mother's cousin, Usui's education was primarily through tutors, partially explaining his academic excellence (as shown when he checkmates the vice president of the Miyabigaoka high school chess club in very few moves).
Diadopsi oleh sepupu ibunya, pendidikan Usui terutama melalui tutor, yang sebagian menjelaskan keunggulan akademisnya (seperti yang ditunjukkan ketika dia memeriksakan wakil presiden klub catur SMA Miyabigaoka dengan sangat sedikit gerakan).