In an average year, Osaka's cherry blossoms reach full bloom around April 4. For a March 11–20 trip, the chance of overlapping peak bloom is ~0%, and the chance of seeing at least some blossoms is ~3%.
Across March 11–20 in an average year, expect roughly 10 days of buds & bare branches. Mostly bare branches with pink-tinged buds — sakura hasn't started here on these dates in most years.
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