In a large bowl, dissolve the yeast and 1 Tablespoon of sugar in the water. Whisk until completely combined.
Add vegetable oil and whisk. Then add 4 of the eggs, whisking for about one minute after each egg is added. Whisk in remaining sugar and salt. Add flour one cup at a time, mixing with a sturdy spoon after each cup.
When all of the flour has been added, turn dough onto floured surface and knead the dough to remove all lumps. Clean out bowl and grease it. Form dough into a ball and return it to the bowl. Let dough rise for one hour in a warm. The dough should approximately double in size. Punch it down and then put chocolate chips in center of dough and reform dough into a ball so that the chocolate chips are encased in the center of the dough. Allow to rise for another 30 minutes.
Remove dough from warm spot and place dough ball onto floured surface. Using a long serated knife, cut the dough in half and then cut each halve into thirds. Reform all six dough balls so that the chocolate is encased in the center of each ball. Then, using your hands, roll out each ball into a strand approximately 15 inches in length. Take three strands and pinch them together at one end, tucking the pinched ends under the bread. Braid the three strands together. When you get to the end of the strands, pinch the strands together and tuck under loaf. Repeat for remaining three strands to create a second loaf.
Lightly grease a large baking sheet. Gently transfer the challahs to the baking sheet. Whisk remaining egg in a small bowl and brush generously onto each challah. Return loafs to warm spot to rise for another 30 minutes.
Preheat oven to 375. Brush challahs with second round of egg wash. Be sure to get egg wash into all the cracks and crevices. Place loaves into oven on middle rack. Fill a baking dish or roasting pan with about two inches of water. Place dish on the rack below the challahs. Bake the challahs for thirty minutes, rotating the baking sheet once in the middle of baking time. Challahs should have a medium golden brown crust and sound hollow when tapped. Be sure to check challahs near end of baking time in order to avoid over cooking. Continue cooking past 30 minutes if challahs aren't golden brown yet.
Cool challahs completely on wire baking rack.