There may be some sellers against that 122.00 level, but remember that trends are fast, directional and tend to go farther than what people expect. Sellers over the last 2-3 weeks have consistently been forced to cover fairly quickly. The price is now up 13 the last 14 trading days (assuming a higher close today). The USDJPY is up close to 740 pips from the March 4 low.
Looking at the 5 minute chart above, at the start of the North American session, the price was consolidating toward the rising 100 bar moving average (blue line). Buyers and sellers had a decision. The buyers won, as they pushed above the high for the day at 121.743, and continued its run to the upside after the better than expected Markit PMI data.
US yields are moving higher with the two year up now 6.2 basis points at 2.162%, the 10 year is also up 6.4 basis points at 2.359%.