This study an editing of a grammatical letter entitled The Rules of Lasyama (especially) and related matters by Ahmad bin Shihab ud-din bin Mohammad as-Sujaee ash-Shafiee al-Azhari (died 1197 A. H.). As-Sijaee maintains in this letter that the noun coming after this particle is either indefinite and has three cases: prepositional complementation (aljar), nominal case (al-Raf) and the objective case (al-nasb) with degrees of recurrence starting from aljar, al-Raf and al-nasb respectively. The noun after this particle could be definite noun and grammarians have agreed that it can have two cases: aljar and alraf and they disagreed over the third case: alnasb. As-Snjaee mentioned all these possibilities illustrating them with examples and differentiating between the strong and the weak in addition to the rules that this particle require such as using () (and) before the particle and the exception of unstressing the / j / sound lasijama /.