Honda is giving nothing away about the possibility of teaming up with Red Bull in 2019.
Red Bull is openly flirting with leaving the Renault camp after this year, and buoyed by the promising early progress of the new Toro Rosso-Honda pairing.
"Toro Rosso is open to new ideas and listen to us attentively," new Honda technical boss Toyoharu Tanabe told France's Auto Hebdo. "We listen to them just as carefully.
"Together we're working hard to achieve our goal."
However, when asked how the Red Bull talks are proceeding, the Japanese answered: "I'm focused on this season and on the technical partnership with Toro Rosso.
"As for everything else, decisions are made in the top management of Honda."
What is clear, though, is that Toro Rosso is happy to be the vehicle for Honda to speed up its engine development, notwithstanding the three engine per season rule.
"Other teams work with two or three major updates per season," Toro Rosso boss Franz Tost told Speed Week. "We pursue a different philosophy.
"We want to make the car faster every time we make small improvements."
The 2018 calendar continues next weekend in Baku.