Total calories (approx): 485 (how calories are calculated) 
Time needed: 10 minutes in the morning
Type: Japanese, vegan (tofu)
This is an all-vegan, fiber-rich bento that is assembled from planned leftovers. That is to say, when I made the stir fried lotus root  (omitting the sesame seeds, because I was out of them, and adding a little dried red pepper flakes) and the vegan nikujaga  for dinner, I made extra so there would be enough for bentos in the following days. Both hold up well for a couple of days in the refrigerator - the nikujaga even improves in flavor. If you prefer the classic meaty version of nikujaga , it also mellows well in the fridge for 2-3 days.
Even the carrot rice is made from leftover rice or from frozen rice, using the microwave method . It’s the only thing I made in the morning, but if you’re really pressed for time you could make it the night before too. Or you could use the rice cooker method and freeze it in advance (see how to freeze rice .)
(Incidentally this bento fulfills a lot of the guidelines and characteristics of sho-jin cooking. It’s all-vegetable based, and has warming (lotus root) and cooling (potato) elements. )
Here’s the man-sized version - with more of each item. This one clocks in at about 700 calories.
If the leftovers have been in the fridge for a couple of days and the weather is warm, heat them through thoroughly and cool before packing. If just made them the night before though you can skip this step.