The RBS 6 Nations victors will be without 15 of their Championship winning squad due to the British & Irish Lions tour of Australia.
And they are missing a host of further players due to injuries, unavailability and the decision to rest some more experienced players.
Ashley Beck and Aaron Shingler are the latest duo to pull out of the tour due to injury and Edwards admits it is a blow.
He expects a stern test in the Far East but has been hugely impressed with Wales’ newcomers.
“It’s definitely a huge test for us going out there,” said Edwards.
“Japan are an improving nation and we have to deal with the heat and the humidity, plus the fact that we will have approaching 30 players missing.
“But we seem to have a resolute bunch of lads and we’ve got up to speed over the past couple of weeks in training.
“As a coach you find you work harder with young, inexperienced players in that there’s more to teach. Sometimes you need a little bit more time with them.
“At the moment we’re pretty pleased with them. The attitude is fantastic. I’m quite impressed by their improvement.”
Edwards has been particularly impressed with Neath centre Dafydd Howels, who he first spotted in an under-18s tournament in Grenoble.
“I saw potential there,” added Edwards.
“He can play a variety of positions and his speed is a stand-out feature as well as his size. There’s also his all-round willingness to learn. So if he makes it I’m going to take all the credit!
“I’m the defence coach for the under-18s as well, so I gave Muckers (Robin McBryde) a call and told him he needs to have a look at this kid. He did that and spoke to a few people.
“There’s always a bolter for a tour like this, particularly if resources are stretched in the way that they are. But even if we hadn’t have been so stretched I think he would have been going anyway because you have to plan for the future.
“He can play outside centre, he can play wing and he can play full-back. He’s just a very talented young athlete and rugby player. “
