The failed clones weren't meaningless. Each failure provided feedback to Shinji, allowing him to fine-tune and correct the chakra he used for stimulation.
That might have seemed inconceivable to most people, but for Shinji, it was simply a matter of putting in a little effort.
As time went on, more and more clones were scrapped.
The operating tables in front of Shinji were either a bloody mess, strewn with gore; occupied by corpses curled up and no longer breathing; or held clones staring blankly at the laboratory ceiling.
Yet there wasn't the slightest trace of frustration on Shinji's face. On the contrary, he looked invigorated, as if these failures had helped him realize something.
Soon, after Shinji used Magatsu to stimulate its chakra, another clone showed a reaction.
It twitched on the operating table, then suddenly opened its eyes, revealing a pair of cloudy whites.
"Hm?"
Shinji murmured in surprise.
He'd thought this clone had failed too, but just as he was about to look away, he noticed that its cloudy eye whites were gradually becoming clear and bright.
Shinji focused on them. A look of surprise came over his face. "This is..."
The eyes in the clone's sockets were neither Byakugan nor the Jōgan he wanted. They were a different dōjutsu Kekkei Genkai, distinct from both.
But soon, the eyes clouded over again, then finally dissolved into bloody water.
"Looks like the state isn't stable enough."
Shinji sighed.
But he wasn't upset. The eyes' appearance just then had been remarkably close to the Jōgan possessed by Boruto Uzumaki in the original timeline.
After collecting his thoughts, Shinji made another adjustment based on what he'd just observed and began stimulating the next clone's chakra.
Before long, this clone opened its eyes just like the previous one, the whites gradually clearing.