Walking along the road to the Land of Earth, Naruto watched the merchants coming and going and asked in puzzlement, "Huh? That's strange. Didn't they say commerce wasn't very developed in the Land of Earth? Why are so many merchants heading there in a steady stream?"
Jiraiya looked at Naruto in surprise. "Well, you're the one I should be asking about that. Why are you asking me?"
Naruto was immediately confused. "Me? What does this have to do with me?"
Seeing that Naruto genuinely seemed not to know, Jiraiya was left somewhat speechless. "When you escorted the Third Tsuchikage to the Land of Iron for the Five Kage Summit, didn't you mention something to him about how his granddaughter could use her Lava Release?"
Naruto sank into thought. "Lava Release? Oh, right!"
Naruto remembered. On their way to the Five Kage Summit, he had recalled the ninjutsu Kurotsuchi used against those Demonized Ninjas. It was her unique ninjutsu, Lava Release, a fusion of water and earth chakra natures that produced something like the cement from Naruto's previous life.
Naruto also clearly remembered the suggestions he had made to the Third Tsuchikage about developing a village, using Iwagakure as an example.
Naruto had told the Third Tsuchikage, "Take Iwagakure, for example. It would actually be pretty easy. Most of its ninja can use Earth Style, so besides taking the usual missions, Iwagakure could also develop its construction industry. Take Kurotsuchi. If the people of Iwagakure studied it in depth, it wouldn't be hard to figure out how to produce the slurry her ninjutsu creates. Mix that slurry with some stones and sand, and you can use it to pave roads and construct buildings. Of course, adding some metal would make it even better."
Naruto had even mentioned using Earth Style ninjutsu