Kirk here. Several reports in English mentioned that the temperature in Kumamoto City rose above 40C yesterday but I couldn't find one that mentioned that it was a record, as many of the Japanese-language reports did. Oh, and I didn't notice until just now that the city broke the all-time record two days in a row! Looks like global warming to me.

--- start translation ---
Kumamoto Prefecture Records Its First-Ever Day of Extreme Heat; 40.0°C in Kumamoto City

At 2:24 p.m. today, August 3, the temperature in Kumamoto City reached a high of 40.3°C, marking the first time on record that Kumamoto Prefecture has experienced a day of such extreme heat.

Warm air aloft, intense sunshine, and easterly winds that make it difficult for cooling sea breezes to reach the area have combined to produce dangerously high temperatures that could be life-threatening.

Kumamoto City had only just set a new heat record yesterday, August 2, when the temperature reached 38.9°C—the highest recorded since observations began in 1890. The city has therefore broken its all-time temperature record on two consecutive days.
--- end translation ---