Looking more and more like there is a gap in the market here. Something that has surprised me. Mind you, one of the strangest parts of getting to know other countries is getting one's head around the wildly different perceptions to and management of risks. The "when in Rome" adage doesn't always cut it.
The idea of customising puncture proof gloves/arm sleeves is becoming more compelling.

Might a better/additional protection to check where the nearest clinic is that would have antivenom?

Around Shinjuku station, there are several shops that sell hiking gear. I always used to get good advice here:
L-Breath ??? | L-Breath

For an all-day hike, I'd want Goretex. But for a kid who's occasionally playing outside that may be overspec.

Not really. The risk is close to nil.

I'd be more concerned about ticks & mukade than I would about snakes. Can't comment on Okinawa, but in 7 years running around Honshu I saw snakes less than half a dozen times. Come to think of it, I saw bears more often.

Try telling that to the 50 or so people bitten in 2016
6.?????????

For purposes of comparison (of risk level), the number of automotive deaths in Okinawa in 2016 was 39
http://www.police.pref.okinawa.jp/docs/2015040700023/

(Of course, I'm trying to compare risk level - I'm not saying that being bitten is comparable to dying).

You are correct to point out that ticks etc. are also a concern.

Thank you for that link, jib71!
It seems that 2016 was a better year than usual for snake bites in Okinawa (the annual figure for the region is usually about 90-100.

Best bit in that first link was the part about snake distribution. Turns out the main "habu" isn't found on Zamami. We're visiting the terrain of her Royal High es, Hime Habu (the Okinawan Pit Viper). Apparently the Hime habu has a weaker venom for which anti-venom isn't produced. Still something to be feared and respected.

The HexArmor Superfabric sleeve arrived earlier today, I've already unpicked and disassembled it. Tried spearing myself with some Japanese scissors and there was no penetration (although a fine needle slips through with no problem). It's a good protective layer, strong, light, breathable, doesn't fray. I'll measure LapChild's legs later and then sew on some Velcro, won't need much work. (Total cost was £13.50 - just under 2,000yen - all in, they usually cost about £70). In short, LapChild will have some budget gaiters made from top of the range materials and mama is even less likely to be spending the rest of her life regretting the decision to take her hiking in the sub tropics.

Impressive. You might want to add an elasticated line to the bottom hem of each gaiter, to prevent them from riding up the leg. On commercially available gaiters, you you pull the line under your heel and attach it to a hook on the hem on other side. You can see the hook on the photo in this thread.
I also recommend embroidering some mongoose designs on them for extra protection.

Better luck next time? :)



(by which I mean good luck on the bear spotting front)