Wenger is currently in the country with his side as part of their pre-season preparations, with the Frenchman having previously managed Nagoya Grampus.
The two sides met in a friendly on Tuesday, with Arsenal running out 3-1 winners, but Wenger believes that football in the country has improved significantly over recent years.
"Japanese football has moved up since I (was) here in 95/96," he said. "Since, Japan has been at a few World Cups and the last one in South Africa they were in a very difficult group and they came out of it.
"They are already now qualified for the World Cup in Brazil, so overall the football there has moved up because of the quality of the work they've made with the youths.
"There are still some weaknesses they have to work on, but that's mainly in the efficiency of what they do.
"But overall, technically, Japanese football is at a world-class level now. You can see that in every international game."
Japan international Ryo Miyaichi scored for Arsenal in their latest warm-up friendly ahead of the new Premier League season and Wenger said the 20-year-old former Bolton and Feyenoord loanee has impressed in training.
"I personally was impressed by his (Miyaichi's) pace, his movement off the ball, his desire to go forward and take on defenders, and as well by his fantastic attitude," Wenger said.
"I was convinced in the first session that Ryo deserved a chance. He has been a bit unlucky because he is not completely 100 per cent fit yet because he has been out with a long injury.
"He had a little knock back at the start of the training but now it will take two or three weeks maximum to get back to his best physically because he has done great work to prepare."
Arsenal's next fixture of their tour is on Friday, when Wenger's men take on Urawa Red Diamonds.
