My friend doing monk seal research on the Pearl & Hermes Atoll (part of the Northwestern Hawaiian Islands chain) discovered a large amber glass float, with blue netting with the marking d6 or 9p. Unfortunately, he can't send me a photo from the island only text emails. We are trying to find the origin or history of it. If that's not enough information, I understand.
Your float should it be around 14 inches in diameter is a Long Line or end line float known as a Hakodate or Hock-a-dot-ee Japanese float from the mid to late 70s. These come in wonderful colors such as a deep olive green, bright green, honey amber, beer bottle brown are just a few of the more intense colors. A nice float and worth on the current market value around the $150.00 range for that particular color. Hope this helps.