The MP-4 irons are the first blade offering from Mizuno since Fall 2011. They’re forged, and have a thick muscle pad located behind the impact area that helps to create a soft feel at impact.
The MP-54 irons are also forged, but they will offer much more forgiveness than the MP-4′s. They’re a compact cavity back iron with a deep undercut that should translate into more ball speed and better performance on mishits.
Fans of Mizuno irons have been asking the company to release an iron that was slightly smaller than its highly praised MP-64 irons, as well as one that was slightly larger than the MP-64′s, which is exactly what Mizuno appears to have done with the MP-4 and MP-54