😀 Okay, anon, so in my completely non-canonical and outsider opinion on this, I actually headcanon that Shikako’s way of describing other people’s chakra is one of the few things that carry on from her previous life/“chakra hypersensitivity.”
The way she/SQ describes chakra in terms of sensations–warm sunshine, static and ozone, glowing embers, descending twilight, bubbling brook–it’s very much like someone trying to explain color to someone colorblind. (Or, at least, what I have been trained to understand in media as someone trying to describe color. I legit have no idea if that’s just a hollywood thing or an IRL thing. The only colorblind people I know have only mild forms of deuteranopia and it’s mostly a problem in trying to figure out where on the spectrum certain colors stop and others begin.)
What is green? It’s freshly cut grass and the calming scent of tea. What is red? It’s passionate like fire, the bright burst of sweetness of strawberries in the summer. Blue is the ocean, cool and deep, etc.etc.
So I always figured that chakra sense is literally another sense that we, as readers in a world without chakra, can only experience via the sensation-descriptions that Shikako/SQ give us.
Which, I think, is also kind of why Shikako is unprecedentedly keen at being a chakra sensor. Kind of like color blindness being able to see through camouflage? Most sensors cannot tell what jutsu was used in a certain place and how long ago and in what direction it went. It is, after all, why Shikako got that special jounin rank.
With other chakra sensors I think their abilities are very in the moment. They can tell you how many people are coming and how far away they are. They can tell you how much chakra a person has left (relative to their capacity) and how much chakra they themselves can exert.
Shikako doesn’t have this. Shikako is known to have a problem with… not controlling her chakra necessarily but… moderating it. Regulating it? If that makes any sense. She has and WILL use every last dregs of her chakra and think she’s still okay to walk around afterwards. She pulls her chakra in to the point where even non-sensor Kakashi gets alarmed, and doesn’t realize how weird that may feel to other people.
It’s also why Jiraiya is VERY CONCERNED that she can sense natural energy since that’s not usually something a non-sage can sense. Shikako perceives human/animal-produced chakra and natural energy with the same “sense” whereas other chakra-sensors can only perceive human/animal chakra. Shikako is using a different sense or is interpreting it in a different way.
So I guess in a very roundabout way I’m saying that other sensors are very baffled by Shikako’s chakra. She has a very active regulation of her chakra–I headcanon that the bouts of her passing out as a child as per Sunshine Sidestories Ch 17 is that she hadn’t yet figured out the trick to subconsciously producing chakra. Or rather, while she was still new to the Naruto world, she was too aware of it and kind of…
You know how when you realize you’re breathing and then you become too conscious of breathing and then your pattern gets all weird until you forget about it and then it’s just back to something you do normally? Yeah. Like, Shikako’s body subconsciously will produce chakra but in the early years she was too aware of chakra because of her “hypersensitivity” and so she had to manually produce chakra until it became (like the enhancing her muscles with chakra, like breathing) just something she could do without thinking. (Which is kind of the “epiphany” she has in the fifth installment of Flip To The Last Page)
Yeah. So, very strange for other sensors. If I had to attach normal chakra sense to a RL sense, it’d probably be sound. Which explains why most normal chakra sensors can’t perceive natural energy because it’s just always there and if you’ve always lived with natural energy then there is no change in “sound” for you to hear so it just gets filtered out. Either that or natural energy is at a “frequency” outside of normal chakra sense the way some sounds can be heard by animals but not humans.
So for these listening chakra sensors, Shikako’s chakra is kind of like listening to someone whose volume kind of jumps all of the place for no perceivable reason. Or maybe if its music then the tempo changes for no reason. With other people volume/rhythm corresponds to how much chakra they have left and how they feel emotionally, with Shikako it’s just kind of all over the place. Sense of hearing also goes with the whole “their sense helps in the moment and even at a range, but not after a period of time” since there’s no leftover sound for them to pick up.
Whereas Shikako’s chakra sense is probably more like RL sense of touch. It’s been said before with trying to follow the “heat” of the earth walking jutsu. And it would kind of explain how she can perceive natural energy even though it’s always around and (minus, perhaps the Dead Wastes of the Gelel shrine) her body has never been in a world without natural energy. Like… people who live in one place their entire lives know what humidity is (or lack thereof, for us desert peeps) and don’t have to know what a different humidity is like to know that the air is wet or dry.
If that makes any sense…
Other chakra sensors look for the changes in chakra around them (like sound is vibrations in the air) and to them Shikako is pretty much that one radio station that doesn’t know how to moderate their volume between songs and doesn’t have a set music genre either.