I have a b blog of over 200k+ post and I moved all post from a specific category to a subcategory, I have also deleted the post from the my main site, so all the post of that category have been moved to a subcategory.
Our analytics show that a lot of crawling errors, and my wp permalink structure for main site is example.com/postname/, while the one for my sub-category is example.com/stack/postname/
The solution I came up with is to redirect all visits for non-existant URLs of main site to subcategory URLs
mysite.com/postname/which does not exist will be redirected to my sub-category url
example.com/stack/postname/this pages are active and have content.
How would I go about this?