Raidou flinched, strangled a yelp, and scrambled to hold his chakra circle together. It shied raggedly away from Kurenai, losing integrity to become a brief, chaotic jumble before he could control it again. The exchange only took a fraction of a second, but unhappy shivers remained. He added more energy to steady his chakra, smoothing and strengthening it against further sucker punches.

“Hmm. That’s enough,” Benihime said.

Kurenai returned to her cushion, flashing a brief, apologetic smile at Raidou. There was a lilt to it that made him think he wasn’t the first she’d thumped in a tender spot.

He withdrew his chakra, relieved to have it settle back into its usual, comfortable channels, and attended when Benihime spoke again.

“Well, you’ll never be a genjutsu-master,” she said. “I hope you’re not disappointed, boy.”

He snorted quietly. “I’d settle for reasonably competent.”

She regarded him, eyes sharp. “Sugita Amane taught that ability in genjutsu derives first from one’s elemental chakra nature, that the Air of thought and will is more naturally predisposed towards manipulation of sense and perception than dull, immutable earth. He was wrong-headed in a number of other ways, of course. I incline more towards the Ninomiya Kayama school of thought: the quality and mutability of chakra matters more than its elemental nature. What did you perceive in the way your chakra interacted with Kurenai’s?”

“Not a lot,” Raidou admitted, reflecting on his dull, immutable earth nature with a rising tinge of annoyance. “It tickled a bit when Yuuhi-san moved through it. I could feel where she was, and that… I moved to make space for her, I think.”

He thought about telling Benihime that he’d read Sugita and Ninomiya, along with just about every non-classified genjutsu text he could get his hands on. I’m not stupid, dammit. But he doubted that would impress her. More likely she’d just ask why he hadn’t figured out the problem himself.

He wondered, briefly, if this was how Ryouma felt when his literacy came under fire.

Still, something almost like approval crossed Benihime’s stern face, just for a second. “Now look for the difference in Kurenai’s,” she instructed.

Kurenai extended her chakra. It spread and filled the room as Raidou’s had, a gentle ripple that made his skin tingle, but instead of sliding around him, leaving room, it slipped over him, a subtle pressure that pressed against his skin, almost sliding under the surface.

He gave her a wide-eyed look.

Kurenai’s crimson mouth twitched, hiding a smile. She withdrew her chakra.

Benihime said quellingly, “Don’t look so startled, boy. She didn’t goose you.”

Raidou was deeply thankful, just then, that it was not in his nature to blush. He cleared his throat and sat up, aiming for a more captainly mantle of composure. “Her chakra’s more delicate,” he said. “And, ah…” intimate. He settled on, “Close.”

His arrow must have hit somewhere near the target, because Benihime gave a satisfied nod. “That’s what Ninomiya never quite managed to put into words. Your chakra—like the chakra of a great many other fine ninja; don’t look so sulky—has a natural repulsion to others. It clings tight to your bones, and will not readily mesh with another's." She held up a closed fist, smacked it gently into her open palm, and let the fist bounce away. "Kurenai's chakra has a more adhesive quality, seeking out and sinking in, like a thousand tiny hooks in each thread." Her open hands touched, fingers meshing together. "That’s the true secret to genjutsu mastery, boy. The rest is just finesse. And practice. You’ll never weave a genjutsu that a decently educated shinobi can’t detect, but I see no reason why you couldn’t learn to break one.”

Hope crested—then fell again. Raidou shook his head. “It’s not breaking that’s the problem. With enough sharp edges, I can break out of almost anything. But sharp edges don’t help if I never see the illusion.” He swallowed an aggravated noise. “I can manage up to chuunin level, just about. But in ANBU— well, I’m sure you got the file.”