Inquiry Regarding Google Calendar API Settings for Retrieving 'Public Holidays Only' Japanese calendar

I am looking for a Java calendar ID for Google Calendar API that returns only public holidays. Japanese Google Calendar settings

• Holiday Calendar content (Japanese Settings)
  • "祝日およびその他の休日"：japanese__ja@holiday.calendar.google.com
  • "祝日のみ"：？
    • need the calendar ID the arrow is pointing to

Calendar Setting and What is included on Calendar ID

Calendar ID is an Unique Identifier for an Entity. Depending on the Setting which is shown on your calendar it will reflect the same thing. I understand that you want to be more specific on what's included as well. On this link Calendar Settings I was able to change the settings about holiday on my solutions created from the past.

Sample Settings:

Reference:

Add or Remove Holiday

Note: Feel free to use what I have shared to accomplish your goal with Google Calendar API, please feel free to add more information with your post this way the community can also share, what is implementation to get the information you are trying to get from Calendar API