The Welshman opened the day just 0.6 seconds ahead of Katsuta. The Japanese driver cut the gap to one-tenth of a second, when he was second on the day's opening stage, won by Finn Kalle Rovanpera in another Toyota.
Evans hit back to take the morning's second stage and, in the afternoon, the penultimate stage of the day.
"OK run, quite difficult conditions," Evans said after the final stage. "I'm just driving well and that's it."
Reigning world champion Belgian Thierry Neuville took two stages in his Hyundai, including the last, to end the day third, 11.5 seconds off the lead.
"It felt OK," said Neuville after the last stage, adding that the leaders were at less of a disadvantage going last.
"The lines are getting cleaner so not so easy to fight with the guys behind."
Ott Tanak was fourth, 15.5 seconds behind Evans, after again complaining of coolant spraying up onto the windscreen of his Hyundai and distracting him.
"It's not been a fantastic day," said the Estonian. "We are hoping for a good night's sleep. I am not sure I need resetting. The car needs resetting."
Frenchman Adrien Fourmaux won the fourth stage of the day, the 12th overall, but had already slipped down the field on the previous stage when he lost 20 seconds after stopping to adjust his chin strap.
He failed to finish the last stage after putting his Ford into a drift. It had to be dug out.
"It's a shame," said Neuville. "We need every car to finish. The risk is there with the speed we're going."