This essay argues that the triple-triangle symbol commonly known as the valknut represents a heart in at least some contexts. Specifically, it is either the ideal, steady heart of the brave slain hero or that of a worthy adversary, and that the word valknut itself may be a heiti for ‘heart of the slain’. Most notably, the metaphor of stone is used as an exemplar for this steadiness in the mythological figure of Hrungnir and his stone heart, while the heroic example is that of Hǫgni, whose steady heart was cut from him while still alive. To support these conclusions, this essay looks at a variety of literary, etymological, and archaeological evidence, including but not limited to Vǫlsunga saga for the death of Hǫgni, Snorri’s Edda for Þórr’s duel with Hrungnir, the possible sources and meanings of the word valknut, Gotland picture stones, and archeological finds featuring the symbol. The interpretation as a heart is compared with that of a binding symbol for the various archaeological sources and is found to be at least as viable. The possibly related symbol of interlocked drinking horns is also briefly explored as an additional depiction of a heart, but one that is connected to Kvasir and skalds instead of warriors.