Andy Farrell says the fitness of James Ryan is an important development for Ireland as they look to build a leadership group for years to come.
Lock Ryan will captain the side having been passed fit to start in Saturday's first summer Test against Japan in Dublin.
He was an injury doubt for the game with an adductor issue.
"I'm delighted for James, it's something that he's unbelievably passionate about," said Farrell.
"He's had two goes at it and he's led the side very well over the last 10 days so we're delighted that our captain has made great progress and is able to join us.
"Hopefully that will stand to us down the years as well as far as the captaincy and the leadership is concerned."
The Irish head coach announced his team for the first of two summer Tests on Thursday, with Ulster's Stuart McCloskey is named at centre alongside Chris Farrell, whose Munster team-mate Gavin Coombes could make his debut from the bench.
A crowd of 3,000 spectators will be allowed to attend the game at the Aviva stadium.
It will be the first time supporters have been admitted to the stadium since February 2020.
Ireland wary of Japan threat after 2019 World Cup defeat
Despite having seven players on British and Irish Lions duty and three other senior players - Keith Earls, Johnny Sexton and Cian Healy - rested, Farrell has named a strong line-up.
Five players - Farrell, Stockdale, Van der Flier, O'Mahony and James Ryan - started against Japan in the last encounter between the two sides at the 2019 World Cup, which saw the host nation stun Ireland in the pool stages.
"We need to be respectful to ourselves. This is a proper Test match, this is a proper side in Japan. We all know [what happened] the last time we played them," Farrell said.
"We obviously need to respect them but we need to respect ourselves first and foremost. We watch training, we watch who comes in and adds to the environment and who puts their hand up to be selected for Ireland.
"I thought they were the best prepared team at the World Cup bar none, and their performances showed that. I believe they had an unbelievably long stint together before that and the players that they picked together to come over for this tour, a lot of them were in that squad albeit they've not played for a good stretch."
Ryan will partner Ultan Dillane in the second row, while Peter O'Mahony starts on the blindside flank and is joined in the back row by Josh van der Flier and Caelan Doris.
The front row is made up by Dave Kilcoyne, hooker Ronan Kelleher and Finlay Bealham.
At half-back Jamison Gibson-Park will partner fly-half Joey Carbery, who returns to the international scene for the first time since the Rugby World Cup in 2019.
Jacob Stockdale and Jordan Larmour start on the wing with full-back Hugo Keenan rounding out the side.
Highly-rated back row Coombes is joined on the bench by Rob Herring, Ed Byrne, John Ryan, Ryan Baird, Craig Casey, Billy Burns and Shane Daly.
Last weekend Jamie Joseph's Brave Blossoms made the British and Irish Lions work hard for their 28-10 victory at Murrayfield.
Ireland: Keenan; Stockdale, Farrell, McCloskey, Larmour; Carbery, Gibson-Park; Kilcoyne, Kelleher, Bealham, Ja Ryan (capt), Dillane, O'Mahony, Van der Flier, Doris.
Replacements: Herring, E Byrne, Jo Ryan, Baird, Coombes, Casey, Burns, Daly.
Japan: Matsushima; Masirewa, Lafaele, Nakamura, Fifita; Tamura, Saito; Inagaki, Sakate, Koo, Van der Walt, Moore, Leitch (capt), Labuschagne, Himeno.
Replacements: Horikoshi, Millar, Ai Valu, Cornelsen, Tatafu, Shigeno, Matsuda, Gates.