@Pontius Navigator
I don't know the airway structure here but an early map showed a possible route passing through or near a number of reporting points. It was said, I believe that these did not represent an airway but a flight along the FIR boundary.
As far as I can tell there is no single airway joining up IGARI and VAMPI. The aircraft would have to fly IGARI-VKB-VPB-GUNIP-VAMPI. 4 separate airways!
Then from VAMPI to GIVAL, you can only fly DCT. If hugging the edge of the FIRs was the aim, it would make much more sense to fly VPB-GIVAL, which are connected by an airway, rather than go via GUNIP and VAMPI which is a dogleg!