Originally Posted by ILUV767
As a pilot I can say this. While operating under IFR Regulations you must be able to fly to your destination with a 45 minute reserve. Now if you have to have an alternate, you must carry enough fuel to fly to your destination, then your alternate at a normal cruise speed and land with a 45 minute reserve. All airlines carry extra fuel reserves but there is a point when you will need to declare "min fuel" which means that any further delay could push you into your fuel reserves.
Again, those are domestic only regulations. Since the flight in question was an international flight to NRT, the regulations are quite different. They include a 10% reserve for the entire cruise fuel, but can get very complicated due to redispatching. Essentially, that is planning a flight to a closer destination (reducing the 10% figure), then redispatching enroute to the actual destination (at which point, the remaining 10% figure is much less).
And declaring minimum fuel does not mean that a further delay will push you into your fuel reserves. It simply means that you can accept no further delay, although you do not need any priority handling. That may or may not have anything to do with the planned reserve fuel, depending on the crew and the situation.