Getting a Japanese Work Visa with Expunged Charges H Visa

I want to get a Japanese work visa. I had a misdemeanor drug possession charge that was dropped and expunged 8 years ago (I was 18 at the time). I also had an assault charge from when I was 17 years old that was also expunged.

My questions are:
Will either of these charges prevent me from being able to obtain a Japanese work visa?
Will immigration officials be able to see either of these charges?
On the application form, where it asks if I have a criminal record, should I say yes or no?

Thanks a lot!