Na adjective confusion

[snoph]

Alright, so I’m currently using Tae Kim’s guide to Japanese to work on my grammar.
I am kind of confused about the conjugation of na adjectives, 好きis used as an example and conjugated in sentences as followed:
ボブは⿂が好きだ。
Bob likes fish.
2. ボブは⿂が好きじゃない。
Bob does not like fish.
3. ボブは⿂が好きだった。
Bob liked fish.
4. ボブは⿂が好きじゃなかった。
Bob did not like fish.

Fair enough. Now what I am confused about is that any other place I look, na adjectives seem to be conjugated slightly differently, such as here:

For instance, in the non past negative for 好きじゃない is used to conjugate.
In the image I uploaded, it is 国が平和ではない

My guess is that both conjugations work for all na adjectives, but have some sort of slight difference in meaning? Anyone who could shed some light?

[YukiPhoenix]

@snoph

For instance, in the non past negative for 好き じゃない is used to conjugate.
In the image I uploaded, it is 国が平和 ではない

じゃ is just a contraction of では.

[snoph]

Ooooh is that so? When do you use じゃ and when では?

[YukiPhoenix]

When you want to be more informal. Any shortening/contracting is basically going to lower the “formality.”

[snoph]

Amazing! Thank you

[YukiPhoenix]

You’re welcome.

[YukiPhoenix]

Also, just to help you along in the future, I found this was a good resource for me on these contracted forms:

List of Japanese Contractions

Because you’re also going to encounter many of those especially if you start reading manga.

For example, ている->てる is a very common one in spoken language.

[ctmf]

Scanning that: super helpful.

Also !

I keep seeing そりや and can’t quite figure out what it means. I’ve almost posted the question several times. But now I see:

Could that be それば, like “if that is so, then…”?
if not then what is そりや or そりゃ, I can’t tell which it is in the vertical handwriting. And I don’t have an example handy right now

[YukiPhoenix]

If it’s actually そりゃ that is a contraction of それは. That falls under the section just after that:

List of Japanese Contractions | Japanese with Anime