This manuscript proposes the S M Nazmuz Sakib Dependency-Focus Principle for Bengali sentence structure and introduces a derived scalar quantity, the Sakib constant, defined over dependency treebanks. Informally, the principle states that in attested Bengali usage, core arguments (subjects and objects) cluster closer to the verbal head than peripheral modifiers (adverbials and clausal adjuncts), and that the ratio between these average distances is numerically stable across corpora. Using real statistics from the UD Bengali-BRU treebank and the Bengali section of the Bengali-Magahi PUD treebank, we define the Sakib constant K Sakib as the ratio between average dependency lengths of core versus peripheral relations, and compute its value for UD Bengali-BRU. Ten figures based on genuine counts and averages illustrate tense and case distributions, relation frequencies, and core versus non-core dependency lengths for Bengali and, for comparison, Magahi. The proposal is presented as a precise hypothesis, mathematically well-defined and empirically grounded in existing treebank data, but still requiring broader testing for confirmation and cross-linguistic generalisation.