For the next week Kenshin did nothing but work. With "Formation Creation" raised to level six huge prospects opened—and huge workload fell on his shoulders. First he reworked sons' suits—making energy blocks more capacious and shields stronger. By his estimates a shield could withstand one full-power strike from an average Jonin—but he knew average Jonin had hundreds of such strikes and far higher speed than even Ichiro could develop.
Kenshin planned implementing collective shield function in suit formations—allowing energy transfer at distance to whoever needed protection, letting them withstand far more than one shield alone. But currently he didn't know how. It required at least weeks of meticulous research and testing—impossible now.
He postponed strengthening his own exo-suit—not planning to leave the refuge soon. He had so much work he sometimes forgot to eat or slept on the workshop sofa. At least six hours daily he spent absorbing medical ninjutsu information—amazing Hitomi again and again with his learning abilities. By her estimates it would take only about one and a half months until Kenshin knew everything she did.
Another sharp (literally) problem was creating at least ten functional katanas so his sons had advantage over other shinobi.
Back in high school browsing this world via laptop screen Kenshin wondered why shinobi used small kunai instead of convenient functional swords capable of cutting enemies in half. The answer was simple: cheapness and convenience.
Katana expense wasn't the main reason most shinobi used kunai—but important. This world's technology was medieval level—so mining, smelting ore, and forging katanas was very costly.
Such katanas dulled and broke even in fights between ordinary people; crossed Genin swords guaranteed shattering into shards versus slightly stronger kunai. Only one thing could help: fuinjutsu.
High-class fuinjutsu masters could strengthen blades many times—letting high-class shinobi shine on the battlefield. But the stronger the shinobi—the harder to create a sword for them.
A Jonin-usable katana cost a fortune and was usually unaffordable for lone shinobi. Elite Jonin katanas weren't even for sale. All cost monstrous money with demand hundreds of times exceeding supply—because strengthening with fuinjutsu was incredibly difficult. Such masters were extremely rare; cost of several years' meticulous work was incalculable.
Almost all Jonin fights were hand-to-hand—ordinary blades broke from one swing, shattering in air. Even if they reached enemy body they did no damage—only slight discomfort like hitting an ordinary person with a dry twig two straws thick.
That's why Kenshin burned with the idea of arming all sons with strongest blades—raising their combat effectiveness 20-30%. But even for him it wasn't simple. First he needed swords of uniform quality—and even then each required its own formation. Everything would be simpler if factory-stamped from same ore by GOST standards. But blacksmith stocks had completely varying ore quality as did hammer strikes; finished katanas varied. For ordinary warriors it didn't matter—but for Kenshin whose formations had to permeate entire blade structure—it was a headache.
All "free" time Kenshin thought how to create a universal formation for all swords at once. Meticulously strengthening each katana for weeks wasn't in his plans—but swords needed ordering now, requiring considerable money.
In days he resumed production of ten- and twenty-year vintage wine—sales he could finally trust to eldest sons. In that time team one completed four missions; all members grew accustomed to outings.
Kenshin tasked sons with finding elite wine sales points during missions to various cities/villages. Best in his opinion was dealing with caravanners often needing escort missions.
He also tasked finding a good blacksmith and negotiating forging ten identical katanas—with condition all forged from provided ore whose processing again fell on Kenshin.
On day 244 Aya and Natsumi gave birth again—to Nineteenth and Twentieth. Both had low talent levels but Kenshin wasn't upset—was glad even for Chunin-potential sons.
On day 245 Kasumi gave birth to twenty-first son with talent level 31—delighting Kenshin who couldn't wait for any son to become Jonin.
On day 248 Ichiro and brothers brought 350 kg iron ore after a mission—spending 40,000 ryo. Wine sales brought 34,000 so iron purchase didn't hurt family wallet much—but money issue arose sharply for first time. By Kenshin's estimates another 100,000 ryo would go for priority blade forging.
In five missions team one earned total 70,000 ryo—but all went to shinobi consumables, primarily shuriken and explosive seals. Kenshin couldn't yet create explosive device analogs—so seals were incredibly important. Each cost 5,000 ryo and could kill a Chunin point-blank. Jonin took almost no damage from explosion—dangerous only near eyes.