I believe you have to obtain a visa in Japan or another country and use that to enter US. I do not think you can obtain a multiple entry visa into US from Canada now. Because (1) US consulate/embassy might refuse to issue you one if they determine your intention is simply travelling to Canada to get a visa; (2) even if they issue you one, it will be a single entry. If you will travel to Japan from Canada, it will work - you will use that for entering US after Japan visit. Do not plan on going back to US before going to Japan - because you would have used it when reentering US.
The risk is, what if US embassy /consulate in Canada denies your visa? Unlike before, you cannot re-enter US simply using the I-94. You would be stuck outside US.
Not to mention that you need to get a visa to enter Canada.
I presume you hold China passport.
The risk is, what if US embassy /consulate in Canada denies your visa? Unlike before, you cannot re-enter US simply using the I-94. You would be stuck outside US.
Not to mention that you need to get a visa to enter Canada.
I presume you hold China passport.