It seems that the meal menu is not available on Business Class meal service page even you are in Japan region (I used both Chrome and Safari).

However I figured on the Japan Region Japanese site there's a page that promotes pre-selected meal in advance, and when you scroll down to the bottom you can access menus.

Here's a link: https://www.jal.co.jp/inter/service/...l/meal_yoyaku/

The only problem is you need to know Japanese But you can check your destination in Japanese by referring back to the flight numbers.