'' I got placed in X division after placements, why ?'' ( guide inside )
Here's a little explanation for all you lost sheep who don't understand how the reset work.
First: it's a soft reset, not a hard reset, so you won't be reset too far off from your current rank
- NOTE FOR HIGHER ELOs: Highest rank achievable via placements is Platinum I
Ok, so now, you got placed lower than your former rank ( maybe by a whole division ) & you don't understand why ( I assume that's why you're reading this post ) ? Here's why, in a simple, dumb down explanation !
So how riot reset rank is they bring your rank closer to 1200 MMR ( elo ) with a soft reset FORMULA USED IN s1 TAKE WITH A GRAIN OF SALT: (x+1200)/2 = y X being your S5 rating + 1200, divided by 2, which will show your previous rating.
Ok, so now let's take me for example. I was plat IV last season right ? Let's say plat IV is 1600. So the formula would be if rounded up: (1600+1200)/2=1400. So I would start my season slightly below my plat IV ranking ( maybe like gold III ? ). Now, you win a LOT & lose a LOT for your first 10 placement matches, like 30. So I would be back to around gold 1 to plat V with 10 wins, but even with a fairly good score of 6-4, I might even drop some ranking and be placed gold IV or something.
IMPORTANT NOTE: KDA doesn't matter, all that matter is W/L
Ok, so now you're thinking '' But why ? I was gold V but placed silver V in my placements while going 6/4 '' ... the problem is your MMR ( elo which is hidden behind your ''division ranking'' ) was most likely bad, how do you know ? If you were winning below 20-25, it mean you were either in the average, or had a very bad MMR ( winning below 15, or even losing more than winning ).
So how so you fix this ? Next season, make sure to have a good MMR, you can check on op.gg an estimate to know if you need to improve your play or if you're doing good or average for your division. Also, if you had a negative W/L ratio ... well you're pretty much 100% sure you had a bad MMR for your division, so it should come as no surprise you ranked lower after your 10 placements.
Thanks for the read & hopefully you understood better how the season transition works now !