A greatly under looked component to jigging is the way the assist hooks are assembled and attached.

Coach Haru:

This is my hook system for the compact tungsten jig.  Blade on jig is super popular in Japan now. It works to imitate tail of fish to swim more realistically. Flashes and spins to appeal. In murky water, fish might not see jig but see blade, blade itself is smaller than jig so if fish attracted to smaller bait it works good. It is popular now because these days there are less jerking jigs. In the beginning of jigging, we used heavy rod and reel, heavy line and jig (like diamond jig) and needed big muscle. Development of jigging focused on light gear. Rod, reel, line, jig, even hooks are going to super light because industries are more marketing jigging fishing for women and children. As well style of fishing. Regular jigging needs a lot of techniques. One pitch jerk, short jerk,  half jerk, long jerk, slow jerk, fast jerk and in Japan each spot has own jerk, Jakajaka maki, Tsushima jerk, Tanabe jerk, Haru’s jerk, etc. But for beginners like women and children, required high skill need to catch fish will keep them away, so industries have developed swimming jigs. Swimming jigs just needs reeling. Jig wiggles and flashes to attract fish. So jig makers took idea from bass fishing to use a blade. It works very well. When nobody have bite the only bladed jig gets bite very often.    

Hirauchi hook is flattened hooks to shine to imitate shirasu ( baby sardine). It creates scene of small jig is biting shirasu, predators see the small fish is vulnerable.  Hirauchi hook Idea is come from making Udon, soba  noodle also famous Japanese swords.  This Hirauchi hook has been developed to use in sabiki and fishing for isagi (chicken grunt). Flattened hook catches water to dance, shines to attract fish. I use for Halalu and other similar size of fish. My friend who owns charter business in Oahu uses Hirauchi hooks for catching opelu. He does not use any flies or plastic worms just those hooks. And he catches a lot. I think he uses gold color. Most people in Japan use regular assist hook. Because Hirauchi is not strong as regular hooks. So its not good for aiming a large fish like pelagic fish. Also edges on hooks make bigger holes that hooks come off easer. Hirauchi is good for not so big fish. The first priority of assist hook is light and strong then appearance is the second. Like ulua, kahala, Ojisan (goat fish) and bottom fish like opaka, onaga suck bait create turbulence that hooks must be light to go into inside mouth. Light hooks the key of it. In Japan,  Hamachi is the most common jigging target. Most assist hook are designed for Hamachi jigging. Here in Hawaii, targeting for ulua better to use light hooks, for pelagic like Ono or Ahi, strength is the priority. 

Fly assist hook. The green tungsten jig in first picture has a fly hook. I use a squid skirt for assist hook, sometimes use it for trail hook like inchiku. The idea is to make fish think artificial jig is eating or chasing plankton or small squid. Often target fish eat very small bait like small baby squid, shrimp, and others. When fish bite, I can feel, fish aimed fly assist hooks or jigs. Most of time, fish nibble during jig falls, fish is aiming fly. Or sometimes doesn’t feel any bites but fish on, that’s another fly hook bite.  When catch Ulua or Kahala, check where the hook on mouth. Assist hook was hooked on lips not inside mouth shows fish didn’t attacked jig. If those fish attacked jig, they suck the jig into mouth it must be deep as length of assist hook or whole jig into mouth. While jigging, and fish attacked violently, the fish attacked jig.