Fired off the GA and switched civics to prepare for Qin.
Our diplomats are already getting a bit reckless with the Chinese in anticipation of fireworks.
Noticed that KK was in red fist mode and reasonably he could only have 1 target. He declares on Qin 4 turns into the set! Now we'll have to jump in otherwise the Mongols get al the booty. Decide to wait for 1 turn seeing if KK asks us to join. He doesn't, so:
Not much later we get Machu Pichu.
Then on the rather eventful last turn of the set we get Physics, no GS though sadly. Selected Artillery as a placeholder.
And look how KK just suicided a whole cavalry stack on Nanjing and what is left inside.

Didn't dare to attack before with only cossacks, they are mighty units but still get terrible odds against riflemen in a city on a hill with huge cultural defenses. So I waited for the cannons and rifles to arrive, but with only 1 unit at 1.1 strength left in Nanjing I did dare to attack with a cossack.

Note by the way that in the pic I got a scouting chariot selected in Shanghai (captured by KK) and all the units KK has in it.
Finally a broader overview of the battlefield.
Our cossacks could attack Beijing next turn (are NE of Shanghai now), but likely Qin will reinforce it and the odds don't look too good without additional units. But maybe KK will suicide some more troops for us, though it's a gamble either way. If we manage to get Beijing we may be able to cap Qin, before he does so to KK. Right now he won't cap (to us at least...).
We could change our civics back now, 1 turn is left of the GA. KK is in free religion, we could go for that as well. Emancipation too. Not sure whether to stay in nationalism or not, although likely when we eventually take on the monsterous Mongols we'll need to draft anyway. Drafted quite a bit during this set, by the way.