In a small saucepan, bring the mirin and sake to a boil and simmer for 30 seconds.
Stir in the ginger, soy sauce and 2 tablespoons of the olive oil.
Remove from the heat.
Season the pork chops with salt and pepper, rub them with the remaining 2 tablespoons of olive oil and grill over moderately high heat for about 6 minutes per side, until nicely charred outside and just pink in the center.
Transfer the pork chops to plates and pour the ginger sauce on top.