Why you should help Japanese business in Europe

The short answer would be the sheer size of investment flowing into your country.
Ministry of Finance in Japan publishes the foreign direct investment (FDI) positions in each region of the world, 19 billion yen outward FDI position out of 124 billion yen outward FDI position went to the EU in 2020 (The data of UK is included for one month in the statistics because of the Brexit date.)

The UK

According to the foreign investment report 2021 published by UNCTAD, the inward FDI ranking of countries is: 1st The United States, 2nd The Netherlands, 3rd Luxembourg, 4th Belgium, 5th UK Offshore Island, 6th Japan, 7th Germany, 8th France. You note the small European economies and UK Offshore Island are ranked high, but the large portions of FDI from these countries are related to financial services and they are not based on dynamic “real” business transactions. In this sense, you could conclude Japan as the 2nd most important foreign investment partner for the UK.

Germany

The inward FDI ranking in Germany is: 1st Luxembourg, 2nd The Netherlands,3rd United States, 4th Switzerland, 5th United Kingdom. However, the large proportion of “real” Inward FDI transactions apart from the financial service is from United States and Japan.