TOKYO, Dec 17 (Reuters) - The Bank of Japan on Friday decided to taper its corporate debt purchases to pre-pandemic levels and scale back some of its emergency funding scheme upon reaching the March 2022 deadline. As widely expected, the central bank maintained its short-term interest rate target at -0.1% and that for 10-year bond yields around 0%. The BOJ last year ramped up purchases of corporate bonds and commercial paper, and pledged to buy at a pace that increases the balance of its holdings by up to 20 trillion yen ($175 billion) until March 2022. It also put in place a separate loan scheme aimed at channelling funds to small firms through financial institutions. ($1 = 113.7200 yen)