There are eight airlines offering flights to Tokyo. The most direct route isn’t necessarily the cheapest – being flexible is key to finding the lowest airfare rates. For example, try searching by month to see the best time of the week to fly. The cheapest date is currently 16 / Apr / 2022.
You can use the filters on your search to see more flights and find cheaper rates – Tokyo has more than one airport. So if you don't need to fly into Tokyo Haneda International Airport, it's worth checking your other options. The 9603 km flight usually takes about 18 hrs.
If you're planning on going to Tokyo during this time, you could take a look at other airport options. Or you could try to get a last-minute bargain.