A more useful way to search the forum is to use a public search engine and add "site:https://retirejapan.com" to the end of the query.
For example:
https://duckduckgo.com/?q=gloabl+index+ ... ejapan.com
This doesn't place any restrictions on the words you can use or the length of the query, and has the benefit of including the blog in the results too.