"Not directly inflationary" does not seem like a very useful thing to say, since QE causally leads to higher inflation.

Japan barely had any inflation for a while because their QE program was temporary, and when it looked like inflation might go above zero, BoJ immediately hiked rates, contracting the economy(2000, 20006). This is how you achieve no inflation.

By the way, recently they've began trying a more expansionary policy once again. Using QE. It is working, so far. It might stop if they dive their head back in the sand!