this/that: ways & sides
The ko/so/a/do direction row for which way, whose side and which of two, each with a polite -chira form.
kotchi
polite kochirathis way; this one (of two)
こっち こちら
Points to a direction, a side or one of two choices (kotchi ga ii), and casually also means 'me, my side' (kotchi wa daijoubu).
kotchi ga ii na.
I'd like this one.
こっちがいいな。
kochira ga ii desu.
I'd like this one.
こちらがいいです。
kochira also introduces people: kochira wa tanaka-san desu.
dotchi
polite dochirawhich (of two); which way
どっち どちら
Asks which of two, or which direction, and takes ga (dotchi ga ii?).
dotchi ga ii?
Which of the two do you want?
どっちがいい?
dochira ga ii desu ka?
Which would you prefer?
どちらがいいですか?
dotchi demo ii means 'either is fine'.
sotchi
polite sochirathat way; your side; you
そっち そちら
The direction or choice on the listener's side, and casually a way to say 'you' without anata (sotchi wa dou?).
sotchi ga ii yo.
Go with that one.
そっちがいいよ。
sochira ga ii desu yo.
That one would be better.
そちらがいいですよ。
sotchi wa? means 'and you?', a casual way around anata.
atchi
polite achiraover there; that way
あっち あちら
The direction or thing away from both of you, used mostly for pointing out the way (atchi da yo).
atchi ga ii na.
That one over there looks better.
あっちがいいな。
achira ga ii desu ne.
That one over there looks better.
あちらがいいですね。
Learn atchi da yo, 'it's that way', first.