I don't really do photos, and can't be bothered with trip reports, but I figured others should benefit from the year of research that went into my epic 2 months Hokkaido back country trip, as there was a lot that I couldn't find online or had no current information for. In no particular order (I.e as things hit my brain) I will add replies or information as to how we went about things, where we stayed and the guides.
I do have some photos which I will upload if relevant. Otherwise, please feel free to engage your own tips and thoughts.
Starting with the hardest to find- Radios.
2-ways use a different frequency in Japan and devices from other countries are strictly prohibited. You require a licence to operate anything over the 1km range (not sure of exact output max) so if you want a radio 500m-1km is the max.
If you know the/a model already then you can find them online, but googling in English does not get you very far. I went to Akihabara on arrival but you would be amazed at how few electrical department stores sell them. To get to the radio district you need to cross into the backstreets of the main road, on the far side from the station, wander around I there and you should be able to find quite a few shops selling them and can compare prices. I actually only found these places after my purchase.
I bought from a helpful man down an alleyway of random assorted cables and wires, just outside the station and around a corner. From memory he was in the building near the pin:

I got 2 long antenna Alinco DJ-P221s. Waterproof, compact, little clip for my backpack and foolproof. They have channels and groups but don't allow you to fine-tune frequencies. Perfectly adequate for 2 and we didn't notice any major range issues in the BC. They are easy to activate whilst riding and were 10 000 JPY each all in.
Please ask away and other questions on radios.
ABS, Avalanche airbags, canisters and trigger/detonation devices:
I've used a bunch of keywords so this comes up in a search, because up to date information is so damn frustrating to find.
Our party of 4 (at its peak) all had new ABS units with full canisters and triggers. These were extremely simple to transit with, thankfully, though I can also report that there is now a retailer in Tokyo and one in Niseko (Niseko 343) so if you want to travel without canisters (or need a new one ) you can buy locally (though Central Hokkaido to Niseko is 4 hours min really).
None of us dared travel with them as hand luggage as it just adds another layer of complexity and the occasional power tripping security guard might decide they weren't safe, but we did experience a range of airlines and airports.
Person 1- SQ in PER, checkin and through checked onto ANA via SIN. pretty easy, showed the MSDS and IATA rules. Had emailed both in advance. Singapore airlines noted it in my booking and ANA said they were fine with it, no need for anything special. Was simple, bag turned up.
Took JAL domestic HND-CTS and checkin was a breeze. Declared dangerous items on checkin, no worries. Had called the Aussie number to add the airbag details which was simple and efficient.
Person 2- TG/ Thai airways at PER, checkin and through checked via BKK to CTS. No hassles at airport or in transit. Emailed in advance to the general Perth enquirers address and had to submit model and dimensions but it was relatively painless.
Persons 3+4- QF to SYD, Japan Airlines SYD-NRT-CTS. Emailed QF DG team on the email listed online. Given details and a printed letter of approval issued. Show this, no hassles apparently. Checkin at SYD was a bit slow, they wanted to check them and had never seem them before, but all in all they arrived safe and sound. Apparently the same happened on the return journey, the staff were very curious about this almost mythical device.
As backpacks go, the ABS vario system is pretty decent. We got 18L and 30l zip on units that seem really well designed and have been used with no hassles. Have not deployed them yet, but I still have a week or so here.
I do have some photos which I will upload if relevant. Otherwise, please feel free to engage your own tips and thoughts.
Starting with the hardest to find- Radios.
2-ways use a different frequency in Japan and devices from other countries are strictly prohibited. You require a licence to operate anything over the 1km range (not sure of exact output max) so if you want a radio 500m-1km is the max.
If you know the/a model already then you can find them online, but googling in English does not get you very far. I went to Akihabara on arrival but you would be amazed at how few electrical department stores sell them. To get to the radio district you need to cross into the backstreets of the main road, on the far side from the station, wander around I there and you should be able to find quite a few shops selling them and can compare prices. I actually only found these places after my purchase.
I bought from a helpful man down an alleyway of random assorted cables and wires, just outside the station and around a corner. From memory he was in the building near the pin:

I got 2 long antenna Alinco DJ-P221s. Waterproof, compact, little clip for my backpack and foolproof. They have channels and groups but don't allow you to fine-tune frequencies. Perfectly adequate for 2 and we didn't notice any major range issues in the BC. They are easy to activate whilst riding and were 10 000 JPY each all in.
Please ask away and other questions on radios.
ABS, Avalanche airbags, canisters and trigger/detonation devices:
I've used a bunch of keywords so this comes up in a search, because up to date information is so damn frustrating to find.
Our party of 4 (at its peak) all had new ABS units with full canisters and triggers. These were extremely simple to transit with, thankfully, though I can also report that there is now a retailer in Tokyo and one in Niseko (Niseko 343) so if you want to travel without canisters (or need a new one ) you can buy locally (though Central Hokkaido to Niseko is 4 hours min really).
None of us dared travel with them as hand luggage as it just adds another layer of complexity and the occasional power tripping security guard might decide they weren't safe, but we did experience a range of airlines and airports.
Person 1- SQ in PER, checkin and through checked onto ANA via SIN. pretty easy, showed the MSDS and IATA rules. Had emailed both in advance. Singapore airlines noted it in my booking and ANA said they were fine with it, no need for anything special. Was simple, bag turned up.
Took JAL domestic HND-CTS and checkin was a breeze. Declared dangerous items on checkin, no worries. Had called the Aussie number to add the airbag details which was simple and efficient.
Person 2- TG/ Thai airways at PER, checkin and through checked via BKK to CTS. No hassles at airport or in transit. Emailed in advance to the general Perth enquirers address and had to submit model and dimensions but it was relatively painless.
Persons 3+4- QF to SYD, Japan Airlines SYD-NRT-CTS. Emailed QF DG team on the email listed online. Given details and a printed letter of approval issued. Show this, no hassles apparently. Checkin at SYD was a bit slow, they wanted to check them and had never seem them before, but all in all they arrived safe and sound. Apparently the same happened on the return journey, the staff were very curious about this almost mythical device.
As backpacks go, the ABS vario system is pretty decent. We got 18L and 30l zip on units that seem really well designed and have been used with no hassles. Have not deployed them yet, but I still have a week or so here.