Collector interest
The closing volume of the Konami GBC series, this Vol.4 released in Japan in 1998 ends the collection with four final Super Game Boy compatible titles. Its value, clearly above the other volumes, makes it the key piece of the set: the hardest entry to find, the one that blocks the completist trying to close the series. The scarcity of an end-of-line print run, rather than the content itself, explains this desirability and the premium paid to finish the collection.