What's the difference between 江 and 河?
江 is mostly used in the South; 河 is mostly used in the North. There are exceptions,  such as 黑龙江, 浏阳河.
Scale. 江 is exclusively for mighty rivers; 河 can be used for both large and small rivers.
All foreign rivers are named with 河.
There is no fundamental differences between 河 and 江.
江 is used for rivers whose banks are steep cliffs; 河 is used for rivers with beaches.
In some classic text, 江 refers to Yangtze river; 河 refers to Yellow River; the other rivers are named with 水, e.g. 渭水


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