OK, I recognise this is probably a rather trivial question under the current circumstances, but it's been bugging me for over a decade!

When rice bags come neatly sewn up at the top and I snip them open, sometimes the thread just instantly falls out in one long piece and other times I have to hack right along the length to get the bag open. What is the right technique to open the bag with one cut?

I understand it might be hard to explain where to cut on a text-only forum but if anyone knows the secret I'd love to find out.

Unraveling those bags are direction specific, pull it from the correct side and it'll come off easily, pull it from the wrong side and itvwill increase your blood pressure.

If you take a close look, one side has only one thread running along the seam while. the other has two. If the single thread is facing you then start from the right side, if it is facing away from you then start from the left.

Examine the leading thread of where you are going to start, the first loop need to be undone first, once you back the lead out of that first loop then gently pull on it and watch it unravel.

Another technique is to simply cut off the lead from the edge of the bag so that you have stubs on either side of the bag and then begin pulling.

Either way, the key is to start on the correct side.

I knew there must be a way. Can't wait to try. Thank you @Trumpster

Even without pics a good instruction ;-)
When, some time ago, I had finally figured out how to do it, the flour company changed their packaging to an other system without thread. Miss now as well my steady in flow of binding wire.