Best known martial artist in Jin Yong universe by *nationality*

[Ken Cheng]

...and by nationality, I consider each distinct Chinese dynasty a different "nation." Also, it's nationality, not ethnicity, so do not be surprised if a nation's representative is not necessarily of that nation's dominant ethnic group.

India - Damo (didn't really appear in any Jin Yong story, but we know that he existed in the context of the Jin Yong universe)

Northern Sung Dynasty - the Janitor Monk

Khitan Liao Empire - Siu Fung

Great Yin Kingdom - Mo Yung Bok

Dali Kingdom - Deun Yu/South Emperor Deun Chi Hing (it's kind of debatable which one of them was the better overall martial artist)

Hsi Hsia Kingdom - Hui Juk

Tubo Kingdom - Kau Mor Tze

Southern Sung Dynasty - Dook Goo Kau Bai

Jurchen Jin Empire - unknown (no representative who would acknowledge allegiance to the Jin Empire, although Central Divinity Wong Chung Yeung, Ancient Tomb Sect Founder Lam Chiu Ying, and North Beggar Hung 7 Gung lived within its borders for a number of years)

Mongol Empire - Golden Wheel Monk

Yuan Dynasty - Cheung 3 Fung

Persia - Three Emissaries of Persian Ming Cult

Ming Dynasty - Dung Fong But Bai

Qing Dynasty - Divine Dragon Cult Leader (DOMD) (?)

[Ian Liew]

Wouldn't Ding Dian, Mei Niansheng or Di Yun have the edge over Divine Dragon Cult Leader for Qing Dynasty? We know Dragon Leader was much better than anyone else during his time, but the Shenzhaojing looked really powerful, so powerful that it didn't even seem to fit in the Qing Dynasty setting.

If Damo doesn't count for India Nemo Singh could run for the position. Do we know what nationality Yin Kexi came from?

[Ken Cheng]

Wouldn't Ding Dian, Mei Niansheng or Di Yun have the edge over Divine Dragon Cult Leader for Qing Dynasty? We know Dragon Leader was much better than anyone else during his time, but the Shenzhaojing looked really powerful, so powerful that it didn't even seem to fit in the Qing Dynasty setting.

Perhaps. I don't know any of those characters, however.

If Damo doesn't count for India Nemo Singh could run for the position. Do we know what nationality Yin Kexi came from?

Quite a step down from Damo to Lui Mor Singh.

Wan Hak Sai was a Persian, but I don't think his skills surpassed those of the three Persian Ming Cult Emissaries from HSDS.

On a related note, however, Lui and Wan's buddy Siu Seung Tze would likely represent the Miu nation.

I just noticed there's nobody to represent Tibet either. That should go to Kau Mor Tze or the Golden Wheel Monk, but they're already representing the Tubo Kingdom and the Mongol Empire, respectively.

[Dirt]

Best Southern Song martial artist should be Wang Chongyang. DGQB is unknown and unproven.

[kyss of the sword]

best known within wulin continuity would be ZSF since he was known far and wide as taiji founder. other skills do not match up in terms of legend.

[CFT]

Kingdom of Yue: Ah Qing

[hyoyatika]

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Jurchen Jin Empire - unknown (no representative who would acknowledge allegiance to the Jin Empire, although Central Divinity Wong Chung Yeung, Ancient Tomb Sect Founder Lam Chiu Ying, and North Beggar Hung 7 Gung lived within its borders for a number of years)

QQR and OYF did represent the Jin. Granted neither were truly loyal, but they did not seem to mind going out and fighting for the Jin's cause. I think it's fair to put OYF here. After all, he was repping the Jin Empire until he went crazy.