Please be aware that Kuala Lumpur and Tokyo has multiple airports and that these results are for all airports serving the city.
The best day to arrive at Kuala Lumpur is Tuesday and it would be best to avoid Thursday, as prices are on average 67.56% higher than on Tuesday. (Average prices, based on 221 datapoints.)
The best time to fly is at around 12. (Average prices, based on 430 datapoints.)