“In general when people don’t know where a painting is, they say it’s in a private collection in Switzerland. That’s the standard response.”

Where is the “Portrait of Dr Gachet” now? Since the historical auction in 1990, the artwork has never been on view to the public again. Its last three decades begin in Japan and lead to an Austrian – and shady business dealings in the Caribbean. Finally, Johannes comes surprisingly close to the work’s present owner in New York. Which is not to say that the “Portrait of Dr Gachet” couldn’t also be in Switzerland.