Here's the scenario.

Assume I have a site, wordpress.site, which has the following Permalink structure: `/%postname%`

Assume I then set up the following posts:

* /post1
* /post2
* /post3

If someone were to type in "wordpress.site/post1/" (extra slash), Wordpress will automatically 301 redirect the user to "wordpress.site/post1".

So far so good. 

But now, let's imagine that there's an old URL "/post4/", and for SEO reasons, I want to create a post for this URL ***and*** keep the trailing slash?

In other words:

* Calling wordpress.site/post4/ does not redirect to wordpress.site/post4 but
* Calling wordpress.site/post4, would redirect to wordpress.site/post4/ and
* Calling wordpress.site/post1 does not redirect, but
* Calling wordpress.site/post1/ would redirect to wordpress.site/post1

How would I go about achieving this?

I attempted to do it by using add\_rewrite\_rule(), but couldn't seem to achieve what I was after (I was still redirected, and yes, I did flush the rewrite rules). Sample code:

```
add_action( 'init', 'my_rewrite_func' );
function my_rewrite_func()
{
    add_rewrite_rule( 'post4/$', 'index.php?p=12', 'top' );
}

```

Any suggestions?