Two years after Haruhiko Kuroda, governor of the Bank of Japan, declared his team will "do whatever it can" to end deflation, it's painfully clear their efforts aren't working.

Stocks are up, bond yields are down and people are buzzing about Japan for the first time in years. What's still missing, though, is any hint of the self-sustaining recovery Kuroda hoped to be touting by now. With annualized growth of 1.5 percent between October and December after two straight quarters of contraction, Japan is hobbling out of recession far more slowly than hoped. A third dose of quantitative easing is almost certain. Here are three reasons why.

First, the initial rounds of QE weren't potent enough. "In order to escape from deflationary equilibrium, tremendous velocity is needed, just like when a spacecraft moves away from Earth's strong gravitation," Kuroda recently explained. "It requires greater power than that of a satellite that moves in a stable orbit." Although the Bank of Japan managed to lower the value of the yen by more than 20 percent beginning in April 2013, that clearly hasn't provided enough of a boost to the economy. (Net exports, for example, added just 0.2 percent to fourth quarter GDP.) Meanwhile, the bank's 2 percent inflation target looks more and more distant. The BOJ's main inflation gauge slowed to just 0.2 percent in January, down from 1.5 percent in April last year.