The Japanese business-investment format adapted into the British show Dragons' Den was Money Tigers.
Money Tigers supplied the basic television structure later used by Dragons' Den: entrepreneurs stand before wealthy investors, explain their business, and ask for capital in return for equity. The British production adapted the presentation style and terminology for its own audience, calling its investors dragons.
The format spread internationally and inspired related programmes in numerous territories. One especially well-known American adaptation is Shark Tank, whose investors are called sharks rather than dragons. Those shows share a broad concept but are separate productions with different panels, broadcasters, and national business cultures.
The Japanese origin is easy to overlook because the British programme developed its own strong identity. Its success came from making valuation and negotiation understandable to a general audience while preserving the uncertainty of a live pitch.