How to Begin a URL With a Hyphen on Tumblrby Alan Sembera
The method for creating a Tumblr URL with a hyphen at the beginning isn't obvious, but you can do it once you know the trick. The trick works only when you create a secondary blog -- you can't do it with your primary blog. Before you put a lot of work into the blog, however, keep in mind that Tumblr makes it hard to create these URLs for a reason; domain names that begin with a hyphen don't conform to generally accepted Internet standards. While your new Tumblr URL may work fine for now, there's no guarantee you won't run into problems down the road.
Sign in to your Tumblr account, click the arrow next to your primary blog name in the right pane, and then select "Create a New Blog."
Enter the title of your new blog in the Title field.
Enter the URL for the blog, including the hyphen at the beginning, in the URL field. Tumblr displays an error message about the hyphen -- ignore it for now.
Add a word before the hyphen -- any word will do -- so that Tumblr no longer displays the error message.
Highlight the word you just added, and then position your mouse pointer over the "Create Blog" button.
Press the "Delete" key and then immediately click "Create Blog." You have to be very quick -- if you're too slow, you get the error message again. Keep trying until you succeed.