Wow, looks like I jumped into this one a little late. I'm not an expert in this, but here's what I've learned for myself thus far:
- Yes, if you're going to INSIST on diving on your own, e.g. pulling over to the side of the road and jumping in, you may be right -- there may not be that much to be afraid of... However having said that, I've heard of divers going out and coming back to find their car windows smashed, tries slashed, and other acts of violence (or theft) done to their vehicle or gear. A good person to ask about this is Jim Goddard with Discovery Divers Tokyo -- he told me quite the tale once... I agree with the poster who mentioned that violence is probably not the best solution here... Ask yourself not whether or not you're intimidated by such bullsh't, but rather, IS IT WORTH IT? Is it really worth the hassle to save some yen? Is it worth your anger and frustration that you're going to have to put up with if someone decides to pull some stunt or other... Which leads me to the next point:
- Unless you're on Okinawa, you still need a place to rent tanks, or if you're one of the rare few who own their own here, fill them, you will still need to deal with the local fishing cooperatives to some degree. They run/operate the standard dive sites, at least in Izu. Can you rent your own tanks? Sure. Run through the hoops, fill out the appropriate forms, agree to their terms, rules and guidelines, and go diving. But of course they'll charge you the standard "ocean entry fee" whether you like it or not. If you take your rented gear "elsewhere" -- as in, not a designated diving spot, I can see how your ability to rent tanks and whatnot could be restricted or disallowed in the future. Another consideration is, this being Japan, we aren't exactly neck-deep in nice, convenient entries. Any sort of "stop-by-the-road" spot may not really be a good entry point, or if it is, you may not be able to park there.
- From what I've been able to figure out so far, through the help of the people on this forum and my own research, is that you can EITHER try to go through the co-op directly, which isn't always easy, the language barrier being the first of several hurdles... But ultimately possible. Otherwise, you can go through a dive shop. Most will insist on sending you with a guide, which will cost you the standard going rate for the area (Izu, specifically Futo is about 12,900 yen for 2 beach dives)... SOME shops allow you to "graduate" to only renting tanks, without a guide... But since there isn't much money to be made this way, they are not easy to find.
The "fishing yakuza" in that sense, fiercely protect their territory (or perceived territory) but at the same time, if you DO play within their rules and pay the money, you also get facilities that stop-by-the-road diving won't afford you -- change rooms, hot showers, rinse facilities and whatnot. Sometimes it makes things just that much more pleasant when you can return your rental tank as soon as you exit the water, rinse your gear, shower, and drink a coffee while you do your logbook at a picnic table provided for the purpose.