The mushhead jig has a shape that holds to the bottom via "point" rather than the side or contour when lowering to the bottom.  This is usually in contact with the bottom so when kept stationary and used along with a trailer such as VIOS, the head wiggles back and forth and left to right even in just a slight current, in a motion that invites a natural reaction from the fish.  The head shakes to the right and left creating  a dog walk action during the small fluttering and impacts that occur during bottom bumping.

Weedguard
3/8oz.

Japanese jigs add dimension to the category

The jig is a lure category that has come a long way since an inventive dude first decided to take his sinker off his line and squeeze it directly to his hook! Anglers and lure makers have tinkered with head shape for the last few decades. But don’t be fooled by the relative simplicity of the jig. The pace of modification and improvement has accelerated dramatically in recent years.

And leave it to the Japanese to adopt the finest components, add features, and find new ways to improve jig performance!

By reshaping heads, altering hook style and size, adjusting hook eye angle, and adding superior paint jobs and skirts, the jig has gone from a generic piece of terminal tackle to a sophisticated, finely engineered artificial lure.