i want an exchange where you hold the private key as well as having the best prices available im not sure if its possible to hold the private key to an exchange but I cant see why they cant implement a blockchain.info wallet and allow people to export their keys
i live in Japan and i want to pay $1000 per week and sell a few bitcoin now and again
I don't think there is an exchange which offer you possibility to hold private key
Exchange need you to deposit your coin to their owned address and give credit on your account to trade
If you hold private key of that address, how can exchange give you credit when they don't have your coin on their possession?
There are many ways to sell and buy bitcoin, localbitcoin is one of those method
you can find another people who interested to buy / sell bitcoin near you
or you can try popular exchange to trade bitcoin, but i think it will hard for you to deposit and withdraw since you live on japan.
Maybe you can ask your fellow Japanese about this in your local forum that talking about bitcoin. Is there any forum like that?
try to ask
here too