It would be nice to know what Shaka would do with his units when we move this way or that---I bet Klarius could predict it from the code

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If we wait, I doubt he'll move. But no matter what we do, we have to protect Pura, unless we can absolutely KNOW that he won't attack it. His impis (2 movement, no slowing for jungle, forest, or hills) can attack Pura immediately, as can his chariots, by moving 2 tiles SE. To stop them we have to have a force 1 NW of Pura (or have bunch in Pura itself, but I don't see any advantage in that). But with 4 impis and 2 chariots, we'd need so many units to block him that we couldn't attack Kwa.
Shaka's going to get Horseback Riding in another turn or two and, if he has any cash, he can upgrade his chariots to horse archers. Now, chariots/Harchers don't get defensive bonuses and our ballistas target mounted units first. We have 2, and he has 2--how convenient. How about we give our 2 phants Combat1 promos, attack his stack from NW of Pura, and then use the second promo to Shock to help heal them in the same turn? We'd have all our other units there too, to protect the phants, with TBD promos. This would be on the current turn, 127.
OK, so now Shaka's chariots are gone. Assuming he stays where he is, he'll have 4 impis and 1 axe in the field and 1 archer in Kwa, plus whatever he's managed to bring up in 1 turn. On turn 128 we'll have 6 or 7 cats, 5 axes, 2 partial (or full) strength phants, 1 full strength phant, and 1 spear that could reach the tile SE of Kwa. We leave 2 axes (probably with Combat I promos) where they are and fortify them, along with a healing phant, to protect Pura from up to 4 impis and 1 axe--ought to be safe, assuming the phant isn't really beaten up, right?
The rest of our stack (3 axes, 7 cats, 2 phants, and spear) moves to SE of Kwa. The next turn (129) we bombard and attack whatever's in there. It may be a couple archers, or maybe Shaka will move his 4 impis in--I don't think his jungle tile 2 NW of Pura is roaded, so his axe won't be able to move in. Whether they stay or fall back into the city, our other 2 axes and phant will be well positioned to either protect Pura or join the city attack.