Shiny patch not appearing, why?

Question

ive encountered more than 100 noctowls and still no shiny one has appeared although the probability of encountering one is high, I'm using the poke radar in platinum

Answer 1

You don't need to encounter up to 100, you only need to get up to 40 and reset the radar over and over again.

While the chance is 1/200 at chain 40, it's still a chance, it's not guaranteed. Just take a break from chaining and leave your DS on & charging, then come back to it.

Comments

So after every 40, you have to break the chain?

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No, that's not it. After 40, you just need to walk around and reset the Poke Radar so the patches of grass will shake again, because walking into a patch could break your chain and give no benefit since the highest chance of getting a shiny is at chain 40 and doesn't increase after that. Resetting the radar doesn't break your chain.
I don't remember in DPPt, but in X&Y even when you encounter a shiny your chain won't break, it'll just reset your chances of finding a shiny.