Started the end of the Xia: the Bamboo Annals' 'three suns' lands on the 1561 BC eruption, but only by chance
Read the current text and the ancient-text fragments of the Bamboo Annals, Wang Guowei's source notes, Mozi, the 1989 JPL work, Keenan 2007 and Pearson et al. 2022. By the current text's own dates, 'three suns rose together' is 1561 BC, the year of the 2022 best guess for Thera; but the line was assembled from Han omen books, the years were set by later scholars, and a sliding test puts the matches at chance (p 0.23). Planet scan agrees with Keenan: 1576 BC had four visible planets together, not five. Open: does the 1561-1550 BC eruption cluster line up with the old memory of drought at the Xia's end? No dated northern Chinese climate record reaches that decade yet.
How it connects
This step led us to
1576 BC: all five planets within 26 degrees, but only 4 degrees from the Sun (unseeable); what could be seen in late December was four planets within 4.4 degrees
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The current text's sky and weather entries land on ice-core eruption years no more often than chance (p = 0.23)
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Ice cores: 1561-1550 BC was the busiest volcanic stretch of 1680-1500 BC (four eruptions in 12 years), and 1561 BC is the 2022 best guess for Thera
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Pankenier's five-planet omen of 1576 BC: our sky check agrees with Keenan, only four planets could be seen
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The 'three suns' of 1561 BC fall in the same year as the 2022 Thera candidate, but only by the current text's own year count, which was built centuries later
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The early books remember failed harvests, mixed cold and heat and a five-year drought at the Xia's end; the ice cores show four eruptions in 1561-1550 BC, about when Erlitou ended
This step came after
Read the 2007 Smithsonian account: the drift result was already known