Here is their Egi squid-catching System in visual format:
See all those colorful jigs? (Jigs are lures made specifically to catch squid.) Do you want to know what is so awesome about them?
Shimano developed 3 colour schemes to cover different environments: “natural” for general presentations, “shrimp/ prawn” when squid require a more realistic presentation, and “Keimura” in deeper water or lower light conditions. The intuitive “Keimura” cloth is activated by UV light. UV light travels further in the water column than sunlight to give your jig more presence and glow where sunlight cannot reach."Shrimp/prawn" is on the far right, above. Do they look any more realistic than the "naturals"? Yeah, not really.
But the real prize for gimmicky marketing goes to the "Keimura." Does UV light really travel further underwater than sunlight? It's a trick question! UV light is just another part of sunlight, along with the human-visible spectrum.
UV does in fact go further than some visible light, because it has such a short wavelength. Long wavelength light (reds and yellows) disappear first, which is why everything looks blue and green underwater. But as you go further and further, UV disappears too. Visible blue light lasts the longest, until it too is finally swallowed up in the black depths.
The Woods Hole Oceanographic Institute has a great explanation of light, especially UV light, underwater. And NOAA has this neat illustration of light attentuation:
Red and yellow are lost first, then violet (and ultraviolet), then green, and finally blue.
Can squid even see UV light? That's a question for another day . . .