The article describes how, in the context of the rapid growth of video consumption on mobile devices and the dominance of portrait screen orientation (9:16), classical cinematographic aspect ratios and techniques must be reconsidered and adapted. While traditional aspect ratios (4:3, 2.39:1) reflected historical technological and aesthetic constraints, the modern user experience dictates new rules of composition, blocking, editing, and technical implementation arising from the characteristics of touch controls and continuous scrolling. The study aims to identify and systematize the principles for applying classical cinematographic techniques in the mobile vertical format, to substantiate their effectiveness, and to develop a new grammar of visual storytelling for the narrow frame. The relevance of this work is driven by the unprecedented growth in mobile video traffic and changes in audience engagement models, which demand scholarly reflection on the aesthetic and technical transformations. Its novelty lies in the comprehensive integration of historical-technical analysis, ergonomic experiments, neurophysiological measurements, and content-analytic data to build a unified model of vertical video language. The methodological foundation combines comparative format analysis, ergonomic tests, a systematic review of recommendations on composition and camera movement, as well as empirical EEG-response studies and statistical analysis of audience behavior on TikTok and Reels. Results show that the central vertical axis of the frame serves as the path of least resistance for gaze and interaction; the rule of thirds transforms into vertical dynamics; and the Z-axis and dolly-in/out techniques become crucial for dramaturgy. Vertical split-screen significantly increases retention;gyrostabilized POV reduces fatigue; light gradients and pinpoint color accents guide attention from top to bottom; and binaural and tactile sound expand perception of the narrow frame. The study’s conclusions establish the theoretical and practical basis of a new cinematographic grammar for mobile vertical video: each modality—composition, camera movement, editing, lighting, color, sound, and interface effects—interacts to precisely direct attention within the 9:16 frame. This article will be particularly helpful to video production specialists, mobile app UX designers, and media aesthetics researchers.