To your average punter, much of Bitcoin remains somewhat of a mystery. Even its creator who goes by the pseudonym Satoshi Nakamoto — who is believed to still hold billions of dollars worth of the currency — is not known to the public.
However that hasn't stopped the cryptocurrency from surging in value recently, becoming a mainstream investment frenzy. And at least one major Wall Street bank thinks Mrs Watanabe is behind the digital currency's meteoric rise in price this year.
But who is Mrs Watanabe?
That term (which borrows a common surname in Japan) is actually used to describe the individual Japanese investor, traditionally a housewife who runs the family's finances and became notorious for her involvement in the foreign exchange (forex) market during the country's prolonged recession in the 1990s.
As Time Magazine wrote in 2013: "Penalised by a tax system that didn't encourage their participation in the labour force, many Japanese women found that they could bolster tight budgets by performing online forex trades in between chores and shopping for groceries."