Do I need an icebreaker at all, or can I just make a run on the server and use my actions to bypass the subroutines?

If you don't mind not having clicks to do other things, sure!

So you don't need an Icebreaker (of sufficient strength) to encounter the ice?

Clicks are a very "expensive" way of breaking subroutines, but useful to have the ability if you don't have an icebreaker with the right keyword.

Of course, Heimdall 1.0 and Ichi 1.0 each have three subroutines so you would have to run on click 1 and use all of your clicks to bypass one of these pieces of ice. Viktor 1.0 only has two subroutines…

Crypsis may be a better option if you have the creds to pump it's strength and break the subroutines - you'll need to spend a click in advance as well - or just make sure you don't run against HB without the relevant Icebreakers

Hurdoc said:

You do not need any icebreakers assuming you have enough actions/clicks to break all the subroutines on the cards.

You encounter the ice, your icebreakers just facilitate breaking the subroutines so they don't affect you.

You can also run without any icebreakers installed. Assuming you don't hit any 'end the run' subroutines, you can even potentially access the server. Either way though, you suffer every subroutine on every ice you encounter.

That said, the HB ice require a bit of work to be really effective. In a competitive card game giving your opponent more choices on how to deal with your tactics and gameplay is generally bad. HB is somewhat balanced by having stronger and more numerous subroutines than other ice, but you're still allowing the runner to essentially use two different pools of resources to deal with them.

The Runner has a basic action called 'Make a Run'.

This action requires only one thing: a click.

The Runner can run with nothing in their rig and no cards in hand and no credits in the bank if they wanted to.