Luckily for him, more than 500 Saudis landed in Tokyo for a state visit last month. The congregation was led by 31-year-old Prince Mohammed bin Salman al-Saud, who just so happened to be looking for new ideas that Saudi Arabia can support, thereby decreasing its dependency on oil and the nation’s other natural resources.

Ahead of the visit, Son, who has built his company into a $68 billion (£55 billion) telecommunications and tech investment giant, asked SoftBank executive Rajeev Misra to look at various sources of funding for the fund that he envisaged.

Misra, who will head up the SoftBank Vision Fund, reportedly asked two ex-colleagues from his Deutsche Bank days, to gauge interest from various funding sources. The former colleagues, Nizar Al-Bassam and Dalinc Ariburnu, then got in touch with senior Saudi officials and a series of meetings were arranged between SoftBank and a selection of Saudi delegates.

How MBS met Masa

Before pitching MBS, Son first of all met with some of the royal court’s closest advisors. During these meetings, Son reportedly pointed to a number of his previous investments — including Alibaba, mobile gaming firm Supercell, and Yahoo Japan — in a bid to reassure the Saudi officials that he can be trusted with investing their country’s money.

Eventually, Son was given the chance to speak directly to MBS, who is reported to be an “admirer of the Japanese culture.” The meeting went well, according to the FT, who cites a source saying: “The plans really took on a life of its own after Masa and the deputy crown prince met … Masa really made an impact on him.”

Six weeks after the state visit, the two billionaires reportedly met in Riyadh, the capital of Saudi Arabia, to launch what is set to become the world’s largest private tech fund.

In theory, the “marriage of minds,” as one FT source described the partnership, will allow Son to put money into promising technologies and for Saudi Arabia to potentially cash in when they become successful.

“Our country is rich in its natural resources,” writes the Saudi prince in a blog post outlining his “Vision 2030” programme. “We are not dependent solely on oil for our energy needs. Gold, phosphate, uranium, and many other valuable minerals are found beneath our lands. But our real wealth lies in the ambition of our people and the potential of our younger generation.”

The powerful duo envisage setting up a SoftBank subsidiary in London to oversee the five-year fund, which will be made up with $45 billion (£37 billion) from Saudi Arabia, $25 billion (£20 billion) from SoftBank, and $35 billion (£28 billion) from other “global investors.”