On 30 September 1609 (3 September in the Japanese calendar), Ieyasu sent Adams to the Onjuku Harbour, Chiba, about 120 miles from Edo, in territory controlled by Lord Honda. This is the harbour, famous even in modern Japan, in which pearl oysters are collected by women divers, who also provided throughout history a remarkable rescue service for shipwrecked sailors. There Adams saw the wrecked vessel, the San Francisco, which had drifted into Japanese waters on 25 July. It had been en route from the Philippines to Acapulco, Nova Espana, with former Philippine Governor Don Rodrigo de Vivero Velasco and 421 other passengers. Initially Adams was alarmed that, after he had ended the Portuguese trade monopoly, here were the Spanish, close allies of the Portuguese and Catholic to boot, turning up near to Edo and Uraga and not to the western ports, as he would have expected. He reassured himself that the Spanish could do nothing from a shipwreck. For a moment, perhaps, he was forgetting his own experiences!

The Spanish governor and all 371 survivors were under the protection of Lord Honda.The governor stayed in his house, but under close interrogation the governor felt they were being confined rather than protected. He was becoming weary of repeating the same answer that his vessel had been wrecked on the way home after his term as governor had expired in the Philippines.

Ieyasu had told Lord Honda that Adams was to be assigned as interpreter. Lord Honda explained to Adams that when these survivors were rescued, they were almost frozen to death. The women divers had pulled them to shore, stripped them of their wet clothes and enveloped them with their own naked bodies until their body warmth returned. Not surprisingly, Governor Vivero records his intense gratitude for this unusual service.

Adams described Vivero to be in his fifties, rather stout, serious-looking and with a big black moustache. However, in his shabby clothes the governor looked wretched. When Adams introduced himself as Miura Anjin in Japanese and William Adams by birth, Vivero was clearly surprised at an Englishman serving as a close retainer to the Japanese ruler. Although Adams was reluctant to interpret for his enemy, Vivero was so unexpectedly friendly that Adams was embarrassed