Mountains cover three-quarters of Japan, with the larger ranges running through the centre of the Japanese archipelago like a spine. Towering above a beautiful lake and archaic temple-studded town emerges the sacred mountain of Kurokiyama - an inaccessible site visited only by the occasional Shinto pilgrim. An ancient, six-story castle, with ceramic tiled hogyo roofing and massive stonewalls, looks down from its strategic position high on the neck of the mountain. A local shogun built it here during the Edo period - it is a fitting setting for a 20th century oyabun like Masahiro Hayamoto. From here he controls his yakuza maneuverings and international arms deals.