100086
I found the following sentence online; it's a comment about three players A,
B, and C that regularly compete against each other.

> Aに勝てるのがBだけでBに勝てるのはCだけなの良いな

To me it seems like the structure of both subclauses (Aに勝てるのがBだけで and
Bに勝てるのはCだけなの) is really similar, so what warrants the change from が to は in
this scenario? Is it the proximity of the latter subclause to the main
predicate?
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2023-06-20T08:55:51.387
100003
2023-06-26T09:05:46.833
33212
question
grammar は-and-が
Alternation between が and は in seemingly identical sentence structure
I think all four possible combinations are fine in this instance. When you use
は, you create a slot that needs to be filled, and then you fill it with the
answer. When you use が, you describe a characteristics of something and then
reveal its identity with your answer (I hope this makes some sense).

For example, if you say `ご飯にかけられるのは、ふりかけなど` You describe something that needs
to be filled (what can be put on rice) and then you fill it (ふりかけなど).

If you say  
`ご飯にかけられるのが、ふりかけ` You describe a characteristic (ご飯にかけられる) and then reveal its
identify (ふりかけ).

This is why this next sentence is slightly odd `ご飯にかけられるのが、ふりかけなど` Because you
are revealing an identity but it is ambiguous (ふりかけ **など** ).

Now coming back to your original sentence, both work because each thing (A, B,
C) is unique.

If we compare

> (1) 空を飛べるのが鳥類などで、海を泳げるのが魚類などで、陸を歩くのが哺乳類など

> (2) 空を飛べるのは鳥類などで、海を泳げるのは魚類などで、陸を歩くのは哺乳類など

IMO (1) is slightly unnatural because you expect something unique (and not
have "etc"), though I wouldn't say it's downright wrong. In contrast (2) has
no issues IMO.

If you make the groups unique, it again reads naturally:

> (3) 空を飛べるのが鳥類、海を泳げるのが魚類、陸を歩くのが哺乳類
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2023-06-23T13:50:57.370
100053
2023-06-23T13:50:57.370
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100003
answer
This is a case where multiple means of emphasis, namely the cleft sentence
structure and だけ, and multiple possibly contrasting statements are making the
choice of the right particles hard, or in a way easy as all combinations seem
fine.

> Aに勝てるの **が** Bだけで、Bに勝てるの **は** Cだけだ。
>
> Aに勝てるの **が** Bだけで、Bに勝てるの **が** Cだけだ。
>
> Aに勝てるの **は** Bだけで、Bに勝てるの **は** Cだけだ。
>
> Aに勝てるの **は** Bだけで、Bに勝てるの **が** Cだけだ。

The first pattern, with が and は in that order as in the original sentence,
sounds to me like it is explaining the rules centering around B. It first
states a characteristic only B possesses, and then goes on to explain another
characteristic of B in terms of its power balance with other things.

The second and third sentences seem to give equal weight to B and C (which
come after が in the second), and A and B (which come before は in the third),
respectively.

Only the last one sounds slightly off to me. The first part seems to focus on
A, but it is not even mentioned in the second part. If anything, the sentence
sounds like an explanation about what C is like, with additional information
about what it is not: It is not the one that beats A because that’s B.

Without だけ, the first combination sounds a bit weird to me, at least unless
someone has asked what B is like to solicit this statement. Otherwise, the
exclusive focus on B in the first part of the sentence seems unwarranted.

> Aに勝てるのがBで、Bに勝てるのはCだ。
CC BY-SA 4.0
2023-06-26T09:05:46.833
100086
2023-06-26T09:05:46.833
43676
100003
answer