I’d only heard of one post-WWII nuke used in combat (a nuclear land mine got tripped on the Sino-Russian border). What’s the other one?
The other one (that we know of that seismographic evidence cannot be dismissed as something else) was probably much the same. What *I’d* read about speculated (with *some* evidence sourced from former Soviet documents that managed to survive the multiple purges) that it was a nuclear self-destruct charge used by the Soviets when the Chinese overran a divisional HQ.
Gah, hit post too soon.
In any case, both the one you’d heard about and the one I’d read about (two separate detonations) *were* in the general vicinity of the Sino-Soviet border.
For those that don’t know: http://en.wikipedia.org/wiki/1991_Sino-Russian_Border_Agreement
http://en.wikipedia.org/wiki/Sino-Soviet_border_conflict
Beyond what Wikipedia says, after the 1969 mini-war, there continued to be skirmishes and even pitched medium-unit battles until well into the late 80s, early 90s.