This is a new replica of the factory original decal. The originals have deteriorated with time, as they are very old. This Decal was only used on the Japan Domestic Models (JDM).
 
This is a Japanese vehicle type approval (homologation) plate for the Yamaha DT1. Literal Translation (line by line): 軽 自動車 Kei jidōsha → "Light motor vehicle" (or "Kei vehicle" / small/lightweight automobile category in Japan) 運 輸 省 型 式 Ⅱ-19 Un'yu-shō keishiki II-19 → "Ministry of Transport Type II-19" 認 定 番 号 Nintei bangō → "Certification Number" / "Approval Number" ヤマハ DT1 Yamaha DT1 → "Yamaha DT1" (the manufacturer and model) What it actually means: This is the official Japanese Ministry of Transport (Un'yu-shō) type approval plate for the Yamaha DT1 (1968–1969 era). It certifies that this specific model (Type II-19) met Japan's safety, emissions, and construction standards for registration and road use in Japan at the time. These plates were commonly affixed to the frame or a visible location on vehicles sold or imported for the domestic Japanese market.
 
The price includes sales tax.