For years, Han Oak has been celebrated by local critics and international tourists alike for its modern take on Korean food — mandu under a crispy lace, fried chicken wings in a instant-ramen-packet-style dry spice, galbi jjim with smoked-and-cured short rib — which has been showcased everywhere from David Chang’s Ugly Delicious to the New York Times. But the space is more than just a restaurant: It was a home. Behind a small door near the bathroom, owners Peter Cho