When sourcing yarn-dyed check shirts, the fabric composition is paramount; look for 100% combed cotton for breathability or cotton-polyester blends for wrinkle resistance. Pay close attention to the yarn count (e.g., 40s, 50s, or 60s)—higher counts indicate a finer, softer fabric. Additionally, verify the fabric weight (GSM) to ensure it matches the intended season (typically 110-150 GSM for standard shirts). Ensure the pattern matching at the seams, pockets, and plackets is precise, as this is a hallmark of high-quality manufacturing.