Hello there Daphneong-san, and thank you for your question.
Due to the complicated nature of the immigration policy at this time, a large majority of companies in Japan (including each of our partner companies) have adopted a simple blanket policy of putting overseas hiring on pause until the borders are more fully opened. Additionally, although select countries, including Singapore, have been removed from the list of areas subject to landing denial, the business and residence tracks for visa approval as well as short-term tourism are currently not underway for Japan, regardless of departure country, preventing any new visitors from entering unless given special permission (e.g., for association with the Olympics or Paralympics, vaccine development, etc.).
Although travel to Japan is difficult at this time, we are hoping that as the global community continues to vaccinate and otherwise protect against COVID, and as the number of cases hopefully reduces, we may be able to welcome candidates such as yourself in the near future.
Please let us know if there is anything else we can do to help clarify the situation.