Kinzo claims that, in exchange for his soul, the witch Beatrice gave him ten tons of gold. Towards the end of his life, Kinzo created the witch's epitaph and displayed it beneath a large portrait of Beatrice in the Ushiromiya Main Building. Anyone who solves the riddle of the epitaph would discover Kinzo's gold and inherit the family headship from him.
In truth, the gold had originally belonged to the Italian Social Republic, a lingering World War II faction who fought alongside the Axis Powers after the surrender of Fascist Italy. The gold was loaded onto a submarine with the intent of preserving it until after the war, however the submarine suffered a chlorine gas leak in transit, killing much of the crew and forcing the submarine to dock at the Japanese military base on Rokkenjima. Kinzo, who was stationed on Rokkenjima at the time, learned of the gold after the damaged submarine began sinking and the remaining Italian soldiers asked the Japanese to help them offload the gold onto the island. This led to a gunfight between the Italians and the Japanese, resulting in the deaths of everyone except for Kinzo and an Italian named Beatrice Castiglioni. Kinzo took a few bars of gold to begin his fortune and later used said fortune to buy the island of Rokkenjima, giving him access to the remaining gold which was still hidden in the remains of the Japanese military base.
- While most of the gold is located beneath Rokkenjima, a single ingot is owned by Krauss Ushiromiya and is hidden away in the Ushiromiya Main Building. This ingot was given to Krauss as proof that the gold exists.
- Not adjusting for inflation, ¥20 billion amounts to only about $200 million by today's standards. However, adjusting for inflation, by 1986, when Umineko no Naku Koro ni takes place, the gold is worth roughly $1.2 billion or around ¥100 billion. Furthermore, adjusted for inflation, by today's standards the gold is worth around $2.6 billion or ¥319 billion.
- Kinzo's gold accounts for roughly 0.005% of all the gold in the world and roughly 0.01% of all the gold mined by humans.