The next few weeks were grueling. Shikaku was a busy man, and I'd thought he was a lazy one, but when he wasn't at work, he somehow found the time and energy to train me till I was too tired and frustrated to continue.

I wish I could say I was performing well. I wasn't. Shikaku somehow had this idea that I should be able to remember literally everything I experienced. If we walked through a room, he wanted me to know how many potted plants had been within it, and where they were placed. How many windows, doors, or other avenues that someone could enter. What color had the floor mat been? Did it have a pattern? What was the name of the first book on the third row of the shelf next to the far window?

I quickly gained a habit of restless, darting eyes, taking in everything around me, and doing my best to memorize it. I was more aware of my surroundings than I'd ever been, in either life. But even so, I didn't have the recall he was looking for. Inevitably, he would come to a question that I couldn't answer. He never got angry, but he didn't seem pleased, either. I had the distinct impression that he thought I just wasn't trying very hard, or maybe that I was deliberately lying to him when I said I couldn't remember something.

His memory was perfect. Or if it wasn't, it gave a damn good illusion of being so. It seemed almost super-human. Was this a Nara trait? I knew the Sharingan was supposed to literally copy everything it saw, but as far as I knew, the Nara were nothing more than abnormally intelligent. And not even all of them, at that. There were smart and dumb Nara, just like any other selection of people.

Unfortunately for my ego, Shikamaru trained with us when he felt like it, and after a few days to get the hang of it, he beat me every time. It was a reminder that my little brother-err, cousin, that is-was a real genius. One day, the imbalance of experience between us would narrow, and he would leave me in the dust. If he applied himself.

It wouldn't have been such a big deal for me to fall behind Shikamaru in this, if Shikaku hadn't been so absolutely convinced that I should be doing better. It was worrying, because I couldn't keep up with what he expected, and he was going to realize that soon. And when he did, he was going to wonder about me. About why I'd so stupidly admitted that I could remember being in the womb. And then, he might wonder about other thing, things I didn't want him scrutinizing too closely, like why I seemed more advanced than Shikamaru, even though I was barely older than him, and wasn't actually as smart.

The worry was exhausting. In addition to the training I was doing on my own, and the continued chakra sensory and shuriken training with Yoshino and Shikaku, the memory testing was wearing on me. I still even had the occasional calligraphy lesson with Yoshino, and I found myself almost completely without rest or downtime.

But I was still doing my best, because I knew that all of it would be useful later. There had to be a way for me to improve my memory. I knew that IQ wasn't static. The brain was malleable, and could be trained or stagnate, just like any other muscle. It's just that the way I was trying it wasn't working, at least not fast or well enough. It didn't help that I also seemed to have hit a wall with Yoshino's attempts to teach me to expand my chakra sensory range into something that would actually be useful.

When Shikaku wasn't around to train me, which was fairly often as he was the Jounen Commander, I did my normal practice, and tried to figure out my memory problem on my own. I had no luck with the latter.

At least physically, I was improving. Shikaku had carved more silhouettes into the bark of the trees around our training area, and I was trying to learn accuracy while moving. It was very, very hard. It made me appreciate how absolutely ridiculous all those action movies I'd seen back on earth were. Shooting a gun with any accuracy while running, jumping, or even driving, was probably a skill far beyond almost every living person on the Earth.

Shikaku was away at work during the time we normally trained shurikenjutsu, so Shika and I trained on our own, making a game of it as always.

"Okay, Shika. This is our last shot," I murmured between breaths, panting. We were both crouched on the ground about ten meters away from the area where the targets had been drawn.

"I've got left," he whispered back, a hand kept warily on his shuriken pouch. We'd been training for almost an hour already, and we were both almost out of shuriken, and almost out of energy.

"Then I've got right," I confirmed. "No time to waste, let's go!" I shot to my feet, pushing so hard I was half tilted forward as I sprinted toward our targets.

Shika was right beside me, arms and legs pumping like a professional sprinter, face drawn into a scowl of effort.

We ran through the clearing, throwing shuriken at the silhouettes carved into the trees as we went. My shuriken all at least hit the "bodies", but a couple of them bounced off the tree trunks instead of sinking in, and my aim was so abysmal I wouldn't have been much use against a real enemy. Still, at least this was something I was better than Shika in.

We slowed after exiting the target area, and turned to walk back and assess our performance. Shika looked from his side to mine and frowned at the difference. "Twoublesome," he muttered on a puff of air, and plopped onto the ground, breathing hard.

I couldn't feel too superior about it, since I not only had a few extra months to build hand-eye coordination, but a huge amount of extra practice in secret. And, of course, the whole adult-in-a-child's-body thing. But who was counting? I figured it was fair enough, since he was a genius. "Up, up," I demanded, reaching down and tugging at his arm.

With some reluctance, he rose, and after we picked up our shuriken we stretched to make sure we didn't pull any muscles-chakra could do the same job, but we weren't supposed to be able to use ours yet-and laid out in the backyard to relax. Cloud-watching.

"I'm so tiwed," Shikamaru said. "Twaining is hard."

"Me, too," I replied simply. But as we lay there in exhausted stillness, my mind started spinning, caught on his words. Wasn't there something I'd heard or read about shinobi using chakra as a booster, to stay awake and keep their performance level high when on long missions without sleep? Obviously, it could also be used as a physical booster, useful for jutsus such as the shunshin, which was extremely high-speed movement. It helped shinobi heal quicker naturally, and stopped us from getting sick from most attacking organisms or viruses.

I sat up.

Shikamaru looked toward me, his expression questioning.

I shook my head at him and stood, pacing in silence. No time to talk, I was having a minor epiphany.

I sat abruptly back down, crossing my legs and closing my eyes. I reached inward, to that still-strange sense of chakra. It was swirling within, the little chakra centers creating energy at a sedate pace. The chakra pooled in my stomach, with smaller amounts running through my body via a system that ran vaguely parallel to my vascular system. As before, the spiritual yin chakra far overwhelmed the physical yang chakra, and where it mixed together it turned yellow. I looked closer, watching as it mixed together, and saw that there seemed to be more yin chakra going into the yellow mix than yang. Which made sense, since I had way more of it to work with. But did it also mean the chakra I was using for jutsu and practice was unbalanced, leaning more toward yin than yang? Was that a bad thing?

I was about to reach for it eagerly, and only stopped myself at the last minute. Before trying potentially dangerous chakra experiments, I should probably take some time to think over what I was doing.

I'd heard a few horror stories from Shikaku about ninja flooding their system with too much chakra, in the wrong way. One genin had been trying to learn the shunshin without supervision, and broken his own knee, backward, from putting too much force into his first step. People went blind from trying to augment their eyesight and flooding the extremely delicate chakra channels till they burst and ruined the small organs.

I also knew there was a difference in yin vs yang chakra, but this was where things quickly got hazy. Yin chakra was of the mind or the spiritual, and yang of the body or the physical. You mixed them together, and then used the full chakra that resulted for jutsu. But I was pretty sure it wasn't quite as simple as that. I believed I'd heard somewhere that genjutsu used primarily yin chakra. Which meant that the ratios between yin and yang mattered. It was the basis of my potential epiphany.

None of the scrolls or books I'd stolen had any advanced information about chakra, as far as I could tell from my study so far. And I couldn't just go asking around about it. So, maybe, some simultaneously reckless-because I was doing it in the first place-and extremely careful experimentation would help me figure it out for myself.

I laid back again and thought about the safest ways to do said experimentation. I needed a method that would allow me to test my different ideas and get credible results. I grinned to myself.

The next day, when Shikaku was at work, and Yoshino had gone to the store with Shika, I finally had a chance to experiment. It had been difficult to sleep because of how caught up I was in my idea. I'd already gone outside to "play" and completely exhausted myself physically so I'd have a good basis for testing. After making sure I was alone and secure in my room, I sat down on my futon and reached inside myself for the chakra in my stomach.

I took some of the mixed chakra, and gently pushed it through my chakra system, letting a little out though the tenketsu in my left forearm, so that it filtered through my muscles. A very little bit. It felt a little funny, and I moved the muscle experimentally, then used both arms to gently squeeze down on the material of the stuffed animal whose insides I hid things in. I squeezed harder, and harder, and the muscles in my left forearm seemed to eat the chakra, fueling them to squeeze harder than I could with my right.

The chakra ran out pretty quickly, and my grip strength returned to normal when it did. I examined my left forearm, but couldn't find much different about it than before I'd funneled chakra through it. It was still a bit sore from my workout, actually.

Next, I reached back to the pool of chakra within me, and instead of calling on the yellow, mixed chakra of yin and yang, I reached for the green of unmixed yin chakra. It resisted my pull. I tugged a little harder, but instead of moving as I wished, it seemed almost magnetized toward the mixing pool of yellow, and tried to slip that way instead.

I stopped for a minute to try and figure out what the problem was. Maybe I couldn't use straight yin or yang chakra? I took a tiny bit of yin chakra, and pulled it toward the middle, doing the same with an even tinier bit of yang chakra. I kept them separate from the rest of the mixing chakra as best I could, though some of it seeped in. It was surprisingly difficult to keep it from just mixing all together with the rest of the combined chakra as it wished, but I mostly succeeded in keeping it separate. It made a really green colored mix, but once it had that little bit of yang, I was able to pull it out and send it through my chakra system. It felt...cooler than normal, though it wasn't actually a temperature sensation. Kind of like mint?

When it seeped into my muscles, I tried the squeezing trick again. This time, it seemed like my strength gave out quicker, as if the chakra mix was faster-burning fuel.

I resisted the urge to smile, as it could just be the placebo effect. I repeated the experiment with normal chakra, and then mostly yin chakra, making the amounts as similar as possible, and counting off the seconds of increased strength. Yin chakra burned faster, again. I allowed myself to smile, then.

Next, I did the same thing, but with mostly physical yang chakra, which came out dark orange, and felt warm, like pepper. I squeezed really, really hard, and it lasted a few seconds longer. I couldn't contain my glee, and had to hop up and bounce frantically around my room while laughing before the giddy feeling subsided. Once I was able, I returned to my spot atop my futon.

I repeated the test a few times, just to make sure. Yang chakra made me stronger, and lasted longer.

Which lead to the obvious conclusion. Yin chakra might make me smarter. It might, in fact, allow me to augment my memory over short periods of time.

But there was a problem. I was afraid to channel chakra to my brain. I could sense the chakra system there, and it was incredibly delicate. Even more so than the parts that fed the eyes. If I pushed more chakra through them, they might not be able to withstand it, and I would give myself brain damage.

My chakra control wasn't good enough that I felt safe trying the equivalent of self brain surgery.

I sighed deeply, but wasn't disappointed for long before I realized that even if I couldn't yet channel yin chakra to my brain, I'd still learned something momentous about chakra in general. Something that I could probably use right away, in fact.

I stared down at the futon below me, and very slowly ran my fingers through the seals for kakuremino, the cloak of invisibility jutsu. Mixed chakra tried to pull up, but I willed more yin chakra out instead, till it was a greeny-yellow chakra that moved up through my chakra system and out through the tenketsu of my hands. Still concentrating, I laid them on the fabric of the futon below me.

Illusion spread out from my hands like a fast-motion ink spill, covering the whole futon, a larger area than I'd expected to be affected with the relatively small amount of chakra I was using.

Before, when I had imagined fathomless, empty blackness, the fabric had turned black, but not turned into the image of a black hole. It still wasn't perfect. But for a second, my heart beat faster, as my irrational brain was convinced I was suspended above a chasm of blackness, like standing on a pane of glass. I held the illusion for a few more seconds, then withdrew my hands, and did another round of frantic, giddy leaping around my room.

I tired out quickly enough that I was reminded of my original purpose. Could I use chakra to decrease my recovery time?

I thought for a second, and then realized that I really had no idea what I was doing. What I was trying to do amounted to healing myself with chakra, which I didn't know even the first thing about. After a few minutes, I decided to just try cycling extra chakra through my body at a slow, constant rate. My body already knew how to heal things, just like the muscles knew how to contract. If it had the extra chakra, maybe it would just naturally use it to do what it was already doing, just a bit better.

Once I started that, I returned to my cloak of invisibility jutsu practice, which came with surprising difficulty. Turns out, it's not easy to do two different things at once with your chakra. Flushing small amounts of chakra through my system and doing a jutsu that required concentration was like rubbing my belly and patting my head at the same time. Except way harder. But I got the hang of it anyway.

2/17/18: This is the last chapter before the bonus Interlude, which is a thank-you for everyone who helped get this story to 100 reviews. It'll be posted on 2/20. The next few chapters are lead-in to the next arc, where Shiori is going to start attempting real change to the timeline. I'm excited for Shiori to expand her world and sphere of influence a little! As always, feel free to talk to me about what you liked, didn't like, and what you think might be coming for Shiori.