Reconstructing the Relationship Between the Heart Sūtra and the Diamond Sūtra

This paper reconstructs the relationship between the Heart Sūtra and the Diamond Sūtra without relying on similarity of doctrinal propositions or on presumed historical affinity. The Heart Sūtra, a hyper-compressed text of roughly 260 Chinese characters, has often been read in commentarial traditions either as a summary of emptiness doctrine or as an ontological declaration. The Diamond Sūtra, in turn, is frequently reduced to an ethic of non-abiding practice or to a paradoxical critique of language. Under the shared assumption that both are simply "texts about emptiness," the two can appear redundant or inconsistent: the Heart Sūtra is prone to be read as nihilistic negation, and the Diamond Sūtra as a simplified injunction not to cling. This study argues that such difficulties arise because prevailing approaches do not sufficiently reflect how each text organizes practice discourse—through opening practice markers, boundary-setting sequences, and closing devices. Methodologically, the paper considers conditions of oral transmission and recitative repetition prior to extensive textualization. It assumes that meaning may be stabilized not only through discursive explanation but also through procedural constraints embedded in repeated practice. Where breath, rhythm, and repetition segment a text into durable units, list structures, parallel negations, and closure mechanisms are especially resilient. Accordingly, rather than paraphrasing the sūtras as doctrinal explanations, this study first identifies the binding rules enforced internally by the texts and then analyzes the functions those rules perform within practice. From this perspective, the Heart Sūtra is read as a constraint-compressed structure organized by a pivot–boundary–closure sequence, with the "emptiness-mark" (空相) as its pivot. "是諸法空相" does not fix emptiness as ontological denial; it functions to block the substantialization of marks (相). The negation chain (無…) is organized not as simple denial of objects but as boundary conditions that block cognitive pathways by which phenomena are reified as attainable entities. The progression from "無智亦無得" to "以無所得故" structurally fixes the target of negation as the reification of wisdom and attainment as possessions. The placement of "無罣礙…究竟涅槃" and the mantra further supports reading the mantra not as an appendage but as a closure device that marks completion of a trajectory and enables repetition within recitative transmission. The four gāthās of the Diamond Sūtra are analyzed as an expanded trajectory that implements the same operative logic through a more extended structure and procedure. "應無所住而生其心" presents non-abiding as a method rule of practice. "若以色見我 以音聲求我…" blocks sensory capture at the stage of verification. The metaphor cluster "如夢幻泡影…" functions as a reiterable corrective device against the substantialization of marks (相) and identity assumptions (四相). Reading the four gāthās as a continuous sequence—goal, method, verification, and correction—shows that the Diamond Sūtra embeds an internal system of verification and correction that anticipates error within practice. The central claim is that the two texts implement the same operative rules at different levels of compression. The Heart Sūtra condenses practice rules into a constraint-compressed form, while the Diamond Sūtra expands them to include verification and correction. Moreover, the same practice event—observation and transition within practice—can be described differently depending on the observational frame. Apparent conflicts in prior discussion can therefore be understood not as competition between different objects but as invisible mismatches among segmented descriptions of the same event. By integrating these segments through transmission conditions and textual structure, this study formalizes prajñā as the operation of regulated observation (觀) and reconstructs the Heart–Diamond relation as complementary implementations of a single soteriological trajectory structured by non-abiding and non-attainment.