Meat, including tonkatsu, tends to shrink when heated, leading to gaps between the batter and meat, causing the batter to peel off. To prevent this, it's essential to pound the pork chops before cooking. However, it's crucial to start with thick pork cuts; pounding too thin results in a less desirable, floppy tonkatsu. Thus, using thick, pounded pork chops is key to ensuring the batter stays intact.