<p>EFL textbook series are often expected to reflect proficiency frameworks in the grammar they make available to learners, yet less is known about how level-specific targets are distributed across volumes, pedagogic sections, and later re-encounters. Using the English Grammar Profile as an external benchmark, this study profiles CEFR B1-level grammar in three Taiwanese senior-high EFL textbook series through a reproducible corpus-linguistic design. A consolidated inventory of 244 B1-linked grammar points was operationalized as rule-based search specifications and applied to a 120,341-token corpus. The analysis examined four aspects of grammatical provision: normalized frequency, distribution across the corpus, pedagogic location, and the timing of first substantial introduction and later recycling. The results show a markedly uneven profile. A relatively small set of targets receives dense and widely distributed support, whereas many others occur rarely, remain localized, are weakly recycled, or do not appear at all. Descriptive cross-series comparisons indicate differences in exposure intensity, pedagogic allocation, and patterns of sequencing and recycling. Across all three series, most B1-level instances occur in meaning-oriented lesson materials rather than on dedicated grammar pages. The study provides a compact framework for textbook evaluation, approval benchmarking, and targeted instructional supplementation.</p>