Mix together the miso, sake, mirin, yuzu kosho, scallions, and sesame oil in a bowl to make the marinade. Pour three-fourths of the marinade into a baking dish or rimmed sheet pan and reserve the rest. Lay the pork chops in the marinade and flip them 4 times to generously coat all over. Marinate the pork chops for 12 hours, or overnight, in the refrigerator.
Preheat a grill to a two-zone fire (medium and hot). Grill the pork chops for about 10 minutes this way: Start on hot heat for about 1 minute, then shift the chops to medium heat. After about 4 minutes, flip the chops and repeat the two-zone grilling on the other side. When the pork is ready, it'll be glossy and juicy on the outside. Test for doneness using "The 'Nick-and-Peek' Method". Let the pork chops rest for about 2 minutes and serve.
Reprinted with permission from The Japanese Grill: From Classic Yakitori to Steak, Seafood, and Vegetables by Tadashi Ono & Harris Salat, copyright (c) 2011. Published by Ten Speed Press, a division of Random House, Inc.