LONDON • To understand a Son, get to know the father, and the story of Asia's most expensive-ever footballer begins with the tale of an also-ran.
Son Woong Jung was a journeyman. He showed sufficient promise to sign for Ilhwa Chunma, one of South Korea's leading football clubs at the time, and make the national Under-23 squad. But his career plateaued and, after an Achilles' injury, he retired at 28.
Korean football disillusioned him. Running and effort were always emphasised: Where was the space to work on technique? So he set up a football school.
His academy focuses on nurturing ability and discards the boot-camp mentality guiding how young players are treated by traditional Korean coaches.
Still he has some gaps to reach the highest level, but he's (still young), strong, quick, he can score goals with his left or right.
PARK JI SUNG, former South Korean international, on Son Heung Min
A coach at the academy is Son Heong Yun, a former player for Halstenbek-Rellingen in Germany, and Son's son.
But the star pupil is his younger boy: "Sonaldo", as his team-mates at Bayer Leverkusen called him.
Sonaldo - Son Heung Min - made an immediate impact at Tottenham Hotspur, scoring three goals in five games. His dad, a strong presence throughout his career, will be noting his progression.
He arrived at White Hart Lane as a slightly different proposition to other Koreans who have prospered in the English Premier League.
Swansea's Ki Sung Yeung is a fine technician and a perceptive footballer who understands where the space is in a game, while former Manchester United midfielder Park Ji Sung had similar intelligence and seemingly limitless energy.
But Heung Min is felt to be superior on the ball to both of them and, with his height and two-footedness, his speed and his confidence on another level in terms of potential.
Spurs reflected this by paying £22 million (S$47.8 million) to secure him from Leverkusen, the fee breaking Hidetoshi Nakata's 14-year record for an Asian player.
The 23-year-old can play as a second or main striker, or on either flank - he made his biggest impact in Germany coming inside from wide to score.
Mauricio Pochettino wants to blend him with another tall, young and flexible forward, Englishman Harry Kane, and he seems ideal for the collective, high-press then counter-attacking style of his new manager.
"He's playing in different positions. He can play with both feet, left and right. He's a player who can press high, with good energy, and has played for managers (notably Leverkusen's Roger Schmidt) with a similar philosophy to me," Pochettino said.
Heung Min's qualities have made him a poster boy in his native Korea, with endorsement deals from adidas, Gatorade and the Korean conglomerate (and Leverkusen sponsor) LG.
Park, who retired last summer, is full of praise.
"He knows how to use his ability. When I played with him (for South Korea), he was younger and had good talent but couldn't use it all on the pitch," the 34-year-old said. "But now he knows what he can do.
"Still he has some gaps to reach the highest level, but he's (still young), strong, quick, he can score goals with his left or right. It's really good to watch him grow up."
Heung Min's history with his national team is not straightforward, though - and because of it, there is a potential time bomb for Spurs.
He played as an 18-year-old in the 2011 Asian Cup, scoring the first of 14 international goals, but the following season, after travelling from Germany to Korea to play just 20 minutes against United Arab Emirates, having just come back from an ankle injury, Son senior intervened.
Woong Jung asked Korea's coach at the time, Cho Kwang Rae, not to select his son.
"Son isn't right for the national team at the moment. I hope he can join them when he matures a bit more," he said.
Cho ignored the plea but Son junior pulled out of the 2012 Olympics to concentrate on his development at Hamburg.
Like Park, who began in Japan, he never played club football in Korea and his estrangement from the national team was furthered when Leverkusen refused to let him play in the Asian Games last year.
They had spent a club record €10 million (S$16 million) to acquire Son from Hamburg and he was already en route to scoring 29 goals in 87 appearances in their colours.
The time bomb is that missing the Olympics and Asian Games denied Heung Min the chance to win exemption from national service.
All Korean males must start a 21-month tour of duty before they are 28 and footballers are exempted only if they win an Asian title or Olympic medal.
At London 2012, South Korea won bronze and became Asian champions on home soil last year. It means the vast majority of leading Korean players, including the national captain Ki, are now exempt but not Son.
He, and Spurs, are left hoping South Korea qualify for the 2016 Olympics and Heung Min helps his nation to a medal as an over-age player. Or for a Korean triumph at the 2018 Asian Games.
THE TIMES, LONDON