TOKYO, Jan 18 (Reuters) - The yield on Japan's 10-year government bond tumbled on Wednesday after the Bank of Japan decided to leave its yield curve controls in place.

The 10-year yield was last down 10.5 basis points at 0.395%, from 0.51% in its previous trade before the BOJ decision to keep the policy ceiling for the yield at 0.5%. (Reporting by Kevin Buckland; Editing by Edmund Klamann)