I disagree. I looked up dates to verify. I suppose if you got your information from mainstream media it would seem like it went as you say. But it is a fact that the spread started in December 2019 [1], and the Diamond Princess data was available in February [2], and lockdowns started in March [3]
1: https://en.wikipedia.org/wiki/COVID-19_pandemic
2: https://en.wikipedia.org/wiki/COVID-19_pandemic_on_Diamond_P...
3: https://en.wikipedia.org/wiki/COVID-19_lockdowns