Just a quick note on the Korean figures. The official figures are published very regularly on the Korean CDC website, in English, here:
https://www.cdc.go.kr/board/board.es?mid=a30402000000&bid=0030
They are very transparent and include the numbers tested, recovered, dead and where in SK they are. I think this is a model that western countries should follow.
They are doing a lot of testing (16,000 yesterday) and over 95% of tests are negative. This suggests that they are finding most of the cases. They'll obviously be missing some, and some results will be false postives or negatives, but there's clearly no "we're only looking at the tip of the iceberg" thing going on.
They haven't published that 5186 number yet (see Chinese news report earlier in this thread), but I expect it will be added soon.
They usually update the numbers twice a day, which is why the numbers reported in the news can be conflicting (they could have "just added another 300 cases" and also "found 500 cases since yesterday").
I've been looking at the epidemic curve and it is almost certainly exiting the exponential growth phase (and should be heading into a typical S-shaped cumulative-cases-over-time curve). The latest daily numbers are high (600 in the last day), but not growing exponentially (would have expected about 1600 daily cases).
This is pretty good news. It suggests that exponential spread will occur if left unchecked (the cultists) but that the control measures in South Korea are effective. I know little about SK culture, but I think that there is no obvious reason why we can't follow similar measures in the west (unlike China, where the government's control of the people is radically different from ours).