If you can enter the jumphole from the Chugoku side, then you will find the jumphole in sigma-13. As my personal experience, I didn't manage to find it in sigma-13 when I was piloting a Blood Dragon ship and I forgot about it afterwards. However, I ran into a similar situation when I was in Cassini trying to find the jumphole to Galileo. And I had to locate it by enter from the Galileo Jumphole to Cassini.