I am a Belgian citizen currently studying in Tokyo.

Hi,
I would like to visit China for about 6 days, with departure date on Thursday of next week (27/04) but I haven't booked anything yet. If I apply for a Visa this Thursday (20/04), I would theoretically receive it on time (since it takes 4 working days). However, can I have the guarantee that there will be no delay (especially considering that Golden week is approaching)?
Thanks for your help,
Cyril