I got a Kuchipatchi on G5 of my Yellow Tama.Connexion.
I started with a Marutchi and gave it average care - sometimes kept its Hunger & Happiness hearts full, sometimes let them drop to 3/4 or 2/4 full.
It evolved into Hinotamatchi (the Punk) and again, I kept the care average until it got to 4yrs & 5 x Training points.
Then I really went overboard on the love and care routines! Full hearts as much as possible, lots of praise, lots of Jump and Dance games (and 1 x punish if it wouldn't play even after snacks).
Tried to clean up messes as soon as poss, better still got it sitting on the loo as often as I could...
Always checked if it beeped for attention and praised/punished as appropriate and got the training points up to 8.
Presto! One Kuchipatchi (or the Duck as we call it in our house...)
I think that you can only get them on odd number generations (G1, G3, G5), so if you're on G2, G4, etc. then there's no point hoping for one!
Good Luck!