In a large bowl combine sesame oil, soy sauce, starter, and stock or broth. Whisk until mixture is bubbly and completely combined.
Add flour to the bowl and mix until a shaggy dough forms.
Knead dough until soft, supple, and slightly tacky (but not sticky). This may take about 10-15 minutes by hand or 6-8 minutes in a mixer with dough hook on medium speed.
Transfer dough to a clear container or bowl. Mark the position of the top of the dough on the side the container with a washable maker or rubber band and cover with plastic wrap or a towel.
Leave dough to rise at room temperature until it has increased in volume by about 50-100%. This may take around 4-6 hours (see note).
Butter a 9×5-inch loaf pan. Lightly flour a work surface. Fill a small bowl with water and use it to wet your hands. Punch down dough and gently release it from the sides of the container. Transfer dough to your floured work surface.
Lightly stretch dough into a square and then roll into a 5x16 inch rectangle. Fold the dough in thirds, bringing the shorter edges in.
Starting from one of the short edges, roll up the dough like a sleeping bag.
Pinch together the seam and the ends. Add more flour to surface and use your hands to roll out dough to a roughly 8-inch log. Place dough seam-side down in the prepared loaf pan. Cover with a damp towel or lightly greased plastic wrap. Allow to rise until about doubled in volume. This may take around 3-6 hours (see note).
When ready to bake, preheat oven to 350°F. Brush the top of the loaf with water and sprinkle generously with seasame seeds.
Bake for about 40-50 minutes, until golden brown and internal temperature is at least 190°.
Allow to cool in pan for 5 minutes. Remove to a wire rack and cool completely before slicing. Bread can be stored in a sealed plastic bag for up to a week at room temperature, or much longer if frozen.