Hm, very interesting.
At first glance thought "modern", but the seller writes "70s" (which means nothing... we've seen LED watches from the 60s or even 50s), and compared with a plastic TI LED watch it could be from the 70s.
If it's modern, it's either inverse or mirrored like the Puma Sirius watches.
If it's really 70s, it's quite probably DSM. But putting an expensive (at that time) DSM in a plastic case doesn't make sense.
I tend to "modern", despite what the seller writes - but I also don't know anything about Japanese LCD watches of the 70s (despite the earliest Seikos of course )
I hope someone knows more.