Why did Rukawa join Shohoku? At the start of the manga, Rukawa was already a legend and contender for "No. 1 High School Ace", but he enrolled at the extremely weak Shohoku, which at the time only had Akagi as a strong player.

Why did he join such a weak team, when he could have had his pick of great schools? One might initially think that he would risk being overshadowed in a strong team, for example by Sendoh if he were to join Ryonan. However, we know later in the story that he had very lofty ambitions - of even entering the NBA - and with such a goal, it wouldn't matter if he were the ace of a single team or not, since he had to outperform all the other aces.

Did Rukawa give any indication why he picked Shohoku in particular? Was it simply because, as a teenager, he made bad choices? Was there something special about Shohoku that I missed? Did the ambition come later, as the character evolved? Or did it make some sense from Rukawa's perspective?
A picture is worth a thousand words...

This is from page 12, chapter 150.