HOKKAIDO, Japan--In the bloodstock world, the battle for succession does not come down to unseemly squabbles in the boardroom. What matters first is what happens on the track, and even when all goes right there, success in the breeding shed is far from guaranteed. Smallish in stature but a Goliath in influence and reputation, the Kentucky Derby and Preakness winner Northern Dancer gave the European breeding industry many stars including, crucially, Sadler's Wells, whose line holds strong predominantly through Galileo (Ire) and his heir apparent, Frankel (GB). Northern Dancer also...