They have a new memo regarding inspection for visit visa. You only have to show your 1.) passport 2.) visa stamped in your passport and 3.) round trip ticket

if the immigration have doubts, they may go to the second inspection, they would ask 1.) your age 2.) educational attainment and 3.) financial capacity to travel

it would be best if you have an invitation letter from any of your acquaintances here.

I arrived here in last thursday (march 8) also in a visit(business) visa, and not encountered any difficulty. but then again, you have to be honest and relax during the interview. HTH