Thanks all for the information.
We are Aussies. The company is not the traditional Japanese style they say
and a lot of foreigners are employed specially from the US.
They do not require employees to learn Japanese but you will get better compensation if you do.
Also working hours is 8 hours only(9-6pm) and most people don't go beyond that despite the company providing free dinner starting 7PM everyday.
Location is Tokyo.
I also got some feedback from friends there about discrimination specially outside Tokyo,
some communities do not accept foreigners as their neighbors.
Also got the same comment about the locals, they are a lot more uptight and kind of robotic in nature compared to HK locals.
They also do not socialise with foreigners and like more to live in isolation.
Also they say if my wife will not work and just stay at home, she will die of boredom because of very limited interaction with other people
I am a HK local who has spent considerable time living overseas, including 5 years in Tokyo. My 2 cents:
1) Japan quality of life are magnitudes about HK's, especially if you care about outdoors, variety of activities, open space, and access to different festivities over the 4 seasons. I'm not talking about your usual superficial comments about cleanliness / politeness etc etc, but rather the range of activities (skiing / hiking / swimming / beach / onsen / BBQ / fishing) that you can do on a normal weekend vs HK.
2) Driving is much easier in Tokyo than HK - though the speed limits are ridiculously low and the traffic fines (even for missed parking times) are *harsh*. Driving in Japan is considered a privilege, not a right. With that said, there are great places you can visit outside Tokyo with a car (just don't do it over a long weekend).
3) International schools in HK are tougher / more expensive to get into, but have higher "pedigree" (say for getting into Ivy Leagues etc) than those in Tokyo; however, the quality of school environment / space etc are much better in Japan.
4) I'm going to be a little un-PC here, but the "foreigner"(gaijin) premium is much higher in Japan than HK. Don't worry so much about the locals shying away from you, you are going to live in Tokyo with an Aussie company - you will be more than fine and actually will get away with much more than a local would. They are incredibly friendly to foreigners, and I can attest to that with my time living there.
5) Foreign groceries and what not will be more expensive, that's for sure.
6) Rent will be a few levels lower than HK for a much higher quality place. That alone is a major difference maker for 90% of your other daily expenses that you might pay higher for in Tokyo.
7) The food is absolutely spectacular, across almost all cuisines (ironically, except Chinese in my mind). I've lived in many metropolitan cities but nothing comes close to Tokyo, in terms of median standards.
8) If you are living in Tokyo, the part about your wife dying in boredom is absolute BS. There is a MASSIVE foreigner community in Tokyo and there is so much to do. Go get a membership at the American Club in Tokyo and she'll make more friends in a month than she would know what to do with. Tonnes of families just hang out there for the whole day as the facilities are so nice across the board and it's right in the center of the city.
9) I have many UK friends who refuse to be sent back home from their expat positions in Tokyo. They simply refuse to give up their quality of life in Tokyo.
10) Go learn a bit of Japanese, a few lines of conversation will return your effort in spades in terms of your enjoyment in the country.