The Wave Sky sits at the soft end of Mizuno's road range, and the 9 is the tallest version yet: 44 mm of nitrogen-infused foam under the heel, a foam wave in place of a rigid plate, and a 6 mm drop. It is built for the runs where protection matters more than pace.
It suits you on recovery days and long easy miles, or as the cushioned half of a rotation when your legs are already tired. The wide platform and the foam wave keep the height from feeling unstable, which is the usual cost of a stack this tall.
You pay in weight. At 290 g it is not a shoe you will want to run a workout in, and it has no interest in going fast.