Hi, actually, I saw that discussion, which is why I phrased me entry as I did (differentiation of "electric bikes" vs. "eBikes", considered different beasts in Japan).
Until recently, electric bikes in Japan basically came in one of the following varieties:
#1 The typical "Mamachari" electric assist bike sold in Japan is for housewives hauling children around, and usually has a very low center of gravity. This makes it unsuitable for using on the road, although you aren't technically supposed to ride them on the sidewalk. They are usually designed for low speed/low performance, and short distances. Most people will only bike within the vicinity of their house, since if they had to bike farther than the nearest station, they may as well just take the train.
#2 Aside from the Mamachari type mentioned above, you can get similar models without the child seats, which are basically low speed pedal assist utility bikes. Usually seen in use by older folks, but these can be genuinely helpful since there are a lot of hills in Japan.
#3 The third type would be another variation that is like #2 above, but used for hauling trailers for delivery. These are typically allowed to have more power.
In general, the bikes have not been for long distance or high performance, so they did not have very large batteries or high performance parts. This is not to say that they were low quality - they tended to last a long time - just that for example, most of them only had three gears at most. The concept was "help people who need help to get up hills", and that was about it.
There are bike enthusiasts in Japan to be sure, but the average person only uses their bike for short distances, and so doesn't really think too much about things like gears, braking, etc. As I am sure many on this BBS know, many hard core bike geeks don't think bikes should be electric anyway, so it was hard to know what demand electric sports bikes (i.e. "eBikes" would have).
Panasonic had been testing the waters for several years with the hurrier line and one other line, but both were basically their normal electrics assist models with slightly better specs.
Meanwhile the eBike trend was going on in Europe, with faster, sexier models being created, and Japan was not participating in this. One day in 2017, Yamaha decided to come out with the YPJ-C. This was basically a normal road bike with power assist. Reviews were mixed, with some liking the fact that they would get assist in a "sports bike", while others complaining that it was an odd mix. One reviewer said "The battery is small enough that you shouldn't think of this as an electric assist bike, it is more of secret weapon, a turbo button to get you up a hill that can be used 3 or 4 times"
Since then they have released other models, you can check here:
https://www.yamaha-motor.co.jp/pas/ypj/concept/index.html
I wasn't so interested in the YPJ-C because I have always preferred mountain bikes. To me, road bikes only work in a rarified theoretical environment where you don't have to jump up and down on and off the sidewalk, etc. I am always scared of breaking the tire, and feel jolted every time I have to jump, etc. Also, I wanted Disc brakes, so I kept my non-electric cross-bike.
Then Panasonic announced the XM-1. This was their first entry, and in fact the first domestic entry at all, into the eMountain bike category. This made quite a stir. Some people simply said "There is no such culture in Japan." (i.e. trying to say that there might be a market in Europe, but not Japan). I saw one article saying something like "What is the target market for the XM-1? Rich middle-aged single divorced males!" etc. In fact, as always, 95% of the news coverage was positive, but it was also just politely copying the press release that Panasonic put out. The main negative commentary was simple: Who would pay $3K USD for an electric bike? Most electric bikes were $1k - $2k. On the other hand, many non-electric Mountain bikes could cost over $2k. Panasonic simply said "We are confident in our pricing", but they could have been bluffing. They also said they were producing only 200 units in the first year, so presumably they weren't so convinced of the demand themselves.
For me, $3k is a lot to drop on a bike, and I could just as soon purchase a moped or motorcycle instead, so I decided to check it out before I bought it. They held a test drive event in Shibuya, which I attended. It was interesting in that they gave us each a bike and then sent us out into the wild, with the only instruction: "Be back in an hour". I took this video at the time:
I rode all around Shibuya, to Ebisu and back, trying to find the biggest hills I could find. Although the maximum power output is regulated by law (in order to keep it classified as a bicycle instead of moped), the performance was much different than a normal electric assist bike, and the response was much faster. This thing was fun to ride, and since it was easy to navigate hills, I knew I could use it for actually getting around even in the summer. I could use it instead of the train sometimes, which is what I was interested in. I could use it to go to work, etc.
I liked the large tires, I loved the disc brakes, I didn't like the separate AA powered light.
One of the things that struck me as interesting was that the charger was basically like a huge laptop charger. (Usually electric bikes in Japan have a kind of dock that the battery drops into).
I was sold, and placed my order as soon as I could.
I have put a lot of videos online of my biking for anyone who is interested:
(most are decidedly not so interesting, though. I only put them up because some friends like to watch them while doing the exercise bike indoors).
As for the 200 units they were not sure they would sell? They sold out in less than a month. After that, suddenly, Yamaha announced their own mountain bike version. In addition, Panasonic announced a road utility bike version (XU1), and another mountain bike version (XM2) with larger handle bars, built in light, and motor with internal gear shifting.
Most recently, they announced the XM-D2, a full suspension model with 2.8" tires. They are only making 100 units of this one, since the price is almost $6k USD.
You can see all of the current products:
http://cycle.panasonic.jp/products/ewm/
I am not sure about the status of the other major Japanese maker, Bridgestone.