If candidates have no theater certificate, then how it get admission in NSD?

The admission procedure at NSD is quite unpredictable. If you have done 6 plays it will help but it doesn’t necessarily mean that you will get selected. 

Let’s say a person has 8 years of stage experience and has done over 20 plays. But there is no diversity. Also, he/she does not have much direction or backstage experience. It’s not likely that he/she will be selected.

However, if you have done 5 plays and have good technical knowledge of theater, then you can get admission easily.