"It was surreal," Kristoffer Koch, who now works as a digital design engineer at Omnivision, told The Local of the moment he realised how much his hoard of coins was worth.
The 5,600 bitcoins he bought in January 2010 for around $27 were worth well over four million Norwegian kroner ($680,000) by the time he decided to sell this April.
Of that, he put 500,000 NOK into buying his apartment earlier this year.
Koch says he started getting involved in Bitcoin shortly after reading the 2008 paper by Satoshi Nakamoto, the fictional name taken by the person, or group of people, who founded the currency.
"It was the original paper that got me interested," he told The Local. "Digital cash has been the holy grail for crypto, but it was always issued by some central time stamp authority, but Nakamoto kind of solved this problem.
"Cryptography and computer security interests me: I'm a technical guy, not an investor. So I just bought a few at that time."
He began mining Bitcoin in late 2009, and then in 2010, he bought 5,600 bitcoin on the then new Liberty Reserve.
"It wasn't meant as an investment, it was some money to play with. The only thing you could buy at that time was alpaca socks, so I just got on with my life and forgot about the whole thing and concentrated on getting a real job instead," he said.
It was only in April that he realised just how much the coins had come to be worth, as for some time he couldn't find key to the encryption he had done back in 2010.
"I was scrambling to find my wallet file, because I kind of had misunderstood the security implications, I had encrypted it with PGP, so it was a struggle to remember the pass key."
As soon as he realised how big his hoard was he rushed to sell.
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"When I saw the double exponential rise, I knew that it was not substantiated, so I was in a bit of time pressure to sell fast, and spread the risk, so I split the risk between Mt.Gox and Bitcoin-24."
Unfortunately for him, Bitcoin-24 was seized by the German authorities, meaning he is still owed some €322,000. But he's not too worried about that, he says.
He's still got some bitcoin left and he's watching the currency develop with interest.
"I didn't sell everything. I still have a foot in it, so it's still exciting to follow all the innovation that's still going on in Bitcoin. It's infrastructure. It's like watching the internet in the 1990s, trying to explain to your mother why this is important."