Please be aware that Osaka and Tokyo has multiple airports and that these results are for all airports serving the city.
The best month to fly between Osaka and Tokyo is September and the most expensive month to fly is July. (Average prices, based on 1143 datapoints.)
The best day to arrive at Osaka is Wednesday and it would be best to avoid Monday, as prices are on average 37.61% higher than on Wednesday. (Average prices, based on 599 datapoints.)
The best time to fly is at around 12. (Average prices, based on 1749 datapoints.)