Buck's posts on branching and merging
Read what Buck has to say about the Hatteras branch/merge model, in the context of the sharing/pinning system in Visual SourceSafe:
https://blogs.msdn.com/buckh/archive/2004/06/14/155403.aspx
He also has a series of example steps to branch and merge, using the Hatteras Command Line Interface:
https://blogs.msdn.com/buckh/archive/2004/06/14/155417.aspx
If you're wondering, you most definitely can merge in both directions - from the branch source to target, or from the target back to source. So, if you have a “main“ tree, and a “version 1“ release branch, you can easily backport new features from main into the version 1 tree, and merge bugfixes from the release branch back into main - neither requires “baseless“ merging.