Icebreakers are a subtype of Program cards that specifically allow the Runner to interact with the Corporation's ice. All icebreakers have an install cost, a memory cost, and a strength.

There are four main subtypes of icebreakers: Fracter, Decoder, Killer, and AI.

Page 16, Column 2, Paragraph(s) 1-3, Core Rule Book
Icebreakers are programs with the icebreaker subtype that the Runner can use to overcome ice encountered during a run. Each icebreaker has a strength, an install cost, and one or more subtypes that reflect which kind of ice subroutine it is designed to break.

The Runner uses icebreakers to interact with and break subroutines on ice. An icebreaker can only interact with ice that has equal or lower strength than the icebreaker.

In addition to this strength requirement, many icebreaker abilities can only be used to break subroutines on particular subtypes of ice. It does not matter if the ice has additional subtypes, provided it has any subtypes referred to by the icebreaker's ability. If an ability does not restrict itself to a subtype, it can be used against any piece of ice.

Page 31, Column 1, Paragraph(s) 5, Core Rule Book
Icebreaker: A program subtype which enables the Runner to break ice.

Using IcebreakersEdit

During EncountersEdit

During an encounter with a piece of ice, the Runner can use paid abilities on icebreakers to break subroutines on that ice to keep him/herself from suffering the subroutines' effects. Before an icebreaker can break subroutines, its strength must match or exceed the strength of the ice. Many icebreakers have paid abilities that increase their strength.

Page 16, Column 2, Paragraph(s) 4, Core Rule Book
Many icebreakers allow the Runner to temporarily increase the icebreaker's strength by spending credits. This helps the Runner deal with stronger pieces of ice, provided he has enough credos to spend. This strength increase lasts only while the current piece of ice is being encountered, unless otherwise noted by card abilities. After an encounter with a piece of ice, the icebreaker's strength returns to the value shown on its card. This applies to any other strength modifiers given by icebreakers as well.

Breaking subroutines occurs during step 3.1 of the encounter. This is the only time at which the Runner may use abilities that break subroutines. In addition, if step 3.1 is skipped in anyway, then the Runner is considered to not have broken any subroutines on the encountered ice at all, even if that piece of ice has no subroutines at that time.

Page 4, Column 1, Paragraph(s) 4, FAQ
The Runner can only break subroutines on a piece of ice during step 3.1 of a run. If step 3.1 of a run is not reached, such as when bypassing a piece of ice, then no subroutines on that piece of ice are broken.

Outside EncountersEdit

The Runner can use paid abilities on an icebreaker to increase its strength outside of an encounter, but it immediately returns to its previous strength.

Page 3, Column 1, Paragraph(s) 11, FAQ
The Runner can boost the strength of his icebreakers outside of an encounter with a piece of ice. However, unless the icebreaker says otherwise, its strength is immediately reset to its previous value.

FAQ 1.5.32Edit

From the FAQ

The Runner cannot, however, use paid abilities on an icebreaker to break subroutines outside of an encounter.

Page 11, Column 2, Paragraph(s) 4, FAQ
Can I spend credits to boost the strength of an icebreaker, or break a subroutine on a piece of ice, if I am about to encounter a Tollbooth during step 2.3 of a run?
You cannot break subroutines outside of an encounter with a piece of ice, but you can boost the strength of an icebreaker.

FAQ 1.0.2Edit

From the FAQ. Also numbers 1.1.23, 1.2.10, 1.3.10, 1.4.10, and 1.5.10

The runner may use any number of icebreakers during an encounter, but an icebreaker's strength is usable only for that icebreaker.

Page 9, Column 2, Paragraph(s) 4, FAQ
Can the Runner use multiple icebreakers on a single piece of ice?
Yes, although there are few situations where this is beneficial. But the Runner cannot use one icebreaker's strength to allow another icebreaker to interact with the ice.
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