Like the great warlord Oda Nobunaga, Yamauchi wanted his vassals to compete with each other. Nintendo once had three hardware development departments plus EAD. Each of these three departments had its own game development team, and Yamauchi made the leaders of these departments compete with each other. This resulted in successes like the Nintendo Entertainment System and Game Boy, but the departments never shared information with each other.
A fascinating look behind the scenes.