As part of the site tune-up, the English side of the website was initially planned to be merged with the Japanese side and be terminated. I had thought of either supplementing the Japanese contents with English translation or doing away with contents in English completely.

This direction goes against the current web trend that calls for dedicated localized pages. It also does not mean that I don't want to post contents in English anymore because I still do ! The main reason I had made the decision was due to the burden and redundancy on my part to update information twice, once in Japanese then in English. I had also set up a separate blog for posting English dedicated articles, but articles are not posted as often as expected. What would you want to post in ENGLISH ONLY in the first place ? lol

Result...I decided to keep the English side of the website.
Restructuring the website to be modular enabled a common content body for both Japanese and English webpages so updating is an one time procedure. Language switching is done using style sheets. The remodeled website has a English side with the majority of contents mirrored and synced, but in English. A look at the Blog postings in the Japanese side and the corresponding English page will hint at what is being done to achieve this.

BTW, This helped.
Rodger Keays.com "Using base href/ with Anchors"- https://rogerkeays.com/blog/using-base-href-with-anchors