Japan

Me and @ninelives just went for a few weeks and a couple people asked me about where was good etc so effort post incoming -

First off - an update on the bike shops in Tokyo

W Base - Really cool little shop. Sort of like a boutique version of the old Tokyo fixed. Stocks Brooklyn, Heavy Pedal and Bombtrack frames. Maybe some others too. Has DA and Sugino bits too, as well as loads of own brand and other shirts/hoodies/hats.
The guys in there were sound to talk too, and both times we went past there were people sitting around on nice bikes. Very 2008 vibe going on.
W BASE on gmaps

Blue Lug - The best shop we went to for buying stuff. Big store with loads of stock, helpful staff who chatted in English. Sold a load of their own brand stuff, the bags looked really good quality. Had loads of components at the best prices we saw (sugino/DA/Suze/nitto - hubs/cranks/chainrings/bars). Definitely worth visiting. Blue Lug on gmaps

LUG - Plus! Blue Lug also run a cafe which is 10 mins walk/5 mins cycle away from ^ that store. Have free wifi, JP beer on tap and did good food. Sort of like LMNH but a bit smaller and more local. Definitely go if you go by the store and are into that sort of thing. We found it sort of hard to find but its on a pretty small cross street and the store front just brilliantly says 'BEER COFFEE' Lug cafe/bar on gmaps

Tempra Cycles - Favourite shop we went to in Tokyo. The staff were the nicest we met. One guy (whose name I've forgotten) had spent time in the UK and chatted to us for ages and loaded us up with stickers and stuff from the store (He also looked helped me with the Keirin but I'll talk about that below).
They stock used NJS frames as well as having some crashed ones on display and other Keirin stuff, the prices were pretty much the same if not a bit better than they are on NJS export (but obvs you can get through customs yourself) there are 3enshos, nags etc. They are also are the guys who anodise NJS hubs themselves.
And they have a bar in the store! Wish we'd gone at night so it was more appropriate to stay for a beer. Tempra Cycles on gmaps

Brotures - BLB tokyo, meh. Round the corner from WBASE.

Sexton - has closed down according to the locals.

Dreamworks - was also either closed down or just very closed on the day we were in the neighbourhood .

Other Stuff -

Cycling - Definitely take your bike if you can. Everyone cycles in Tokyo, Kyoto and Nara and its clearly the best mode of transport. But remember that your bike needs two working brakes and be prepared to ride mainly on pavements and through clouds of seemingly insane locals (there doesn't seem to be any discernible rules, but its fun). One of the WBASE guys had br8less installed but told me he just rode fast if he saw cops. If taking your bike isn't practical you can rent 'Mamacahri' bikes for like £3 a day from shops/hostels everywhere and thrash it around on those, we did this and it was super fun.

Keirin - I'd heard mixed reports about this so was unsure if it was worth going (especially if you were gonna have no idea what is going on). I'd say it definitely is. One of the guys in Tempra Cycles looked up what races were on for me, and told me which one to go to (which probably helped me a lot). I asked him if he thought it would be worth going and he said 'yes go, drink beers eat some food.' Which I did and it as totally worth it. Its 200 yen to get in the one I went to and beer was like £3 and food on sticks was good. I had no idea what was going on with the betting system which is the only reason locals go (the majority watched the races on TV screens). I went to Matsudo Veledrome, which is the furthest out of Tokyo (of the three that are nearby) but it was only an hour on the tube and super easy to find and everyone there was a mixture of super friendly/confused as to why I was there.
Its pretty much like going to the Dog Track with NJS replacing greyhounds and feels like Herne Hill on Acid.
If you want to go, get someone fluent in Japanese to look up which days you should go, the races operate over three days and the schedules are pretty much opaque to non-speaker.

Food - Is amazing. Go everywhere and just gesture at things, most places seem really okay with this and have big picture menus for pretty much this reason. Don't be snobbish about trying the western food out there too, Mos Burger is amazing.

Accommodation - We stayed in a mixture of Hostels, Air Bnb and one Guesthouse. In Tokyo we stayed here for a few nights Nui and if/when I go back to Tokyo I'd probably book in there for the whole time, was super nice, cheap and cool.

That's about all I can think of right now. Its an amazing country and I definitely want to go back.

@shinkuu_kiss took us out for a night around his local area in Tokyo and it was hilarious and involved Horse Sashimi and loads of sake. Thanks again!

@Chak hope this helps for your trip, give me a shout if you want to know about any other less cycle specific stuff.

TLDR - go to japan