Joseph, who has named his 31-man squad, said playing against heavyweights like New Zealand and Australia over the past four years had helped them develop the mental and physical toughness needed to compete at the global showpiece.
The Brave Blossoms took the Pacific Nations Cup earlier this month by trouncing Fiji, Tonga and the United States, moving up to ninth in the world to match their highest-ever ranking ahead of the Sept. 20-Nov. 2 tournament.
They will have their final warm-up before the World Cup next week against South Africa, the team they famously stunned in 2015 in the biggest upset in the tournament's history.
"We're under no doubt that the South Africa game is an absolutely different level and so is the World Cup," Joseph said.
"We understand it's a very difficult challenge, it hasn't been done before," he said of Japan advancing to the knockout stages.
"But I guarantee the players and staff will give 150%. Whether that will be enough, time will tell."
Japan came close to reaching the last eight four years ago in England, equalling the Springboks and Scotland on three wins in their group but failing to advance due to a lack of bonus points.
Next week's match against South Africa - their first meeting since four years ago in England - will serve as a key test of how his side respond to adversity, Joseph said.
"I don't look at the South Africa game as a must-win game. I look at the South Africa game as a must-perform game," he said.
Japan will open their World Cup campaign against Russia on Sept. 20 in Tokyo where loose forward Michael Leitch will captain the Brave Blossoms for the second successive World Cup.
Luke Thompson, the 38-year-old New Zealand-born lock, was handed the chance to play at a fourth Rugby World Cup and is one of the more experienced players on the roster.
Forward Takuya Kitade, one of three hookers in the squad along with Shota Horie and Atsushi Sakate, was the only uncapped player.
Joseph's side will also play Ireland, Samoa and Scotland in Pool A.
Forwards - Michael Leitch (captain), Keita Inagaki, Yusuke Kizu, Jiwon Koo, Isileli Nakajima, Asaeli Valu, Takuya Kitade, Atsushi Sakate, Shota Horie, Luke Thompson, Wimpie van der Walt, Uwe Helu, James Moore, Hendrik Tui, Yoshitaka Tokunaga, Pieter Labuschagne, Kazuki Himeno, Amanaki Mafi.
Backs - Kaito Shigeno, Fumiaki Tanaka, Yutaka Nagare, Yu Tamura, Rikiya Matsuda, Kenki Fukuoka, Ataata Moeakiola, Lomano Lemeki, William Tupou, Ryoto Nakamura, Timothy Lafaele, Kotaro Matsushima, Ryohei Yamanaka.