Another theory is that 'Uzu' was written using the kanji character for 'thick,' indicating that the Hata clan established their foothold in this region, while 'Masa' was written using the kanji character for 'Hata' of Hata clan; resulting in the region being called 'Uzumasa.'
秦氏の拠点であったことから、拠点という語義を「太い」という字で表し、「まさ」は秦氏の「秦」をもって表記し、「うずまさ」と呼ぶようになったという説。