Why is Kong using a Japanese surname?

Question

In the epilogue to Ping Pong, we see this newspaper headline.

Five years after naturalization, finally a ticket to the Olympics for Tsujido Wenge

Now, I don't know Japanese, but I can kind of read this at the very beginning of the Japanese text:

辻堂文革（中国名 孔文革）

This translates to

Tsujido Wenge (Chinese name Kong Wenge)

This suggests that Kong Wenge is known as "Tsujido Wenge" in Japan. This is because it doesn't make sense for 中国名 to simply be referring to the Chinese characters (the kanji) for his actual name to me, given the "中国" (i.e. "China" or "Chinese" in the sense of nationality), but again, I don't know Japanese.

Is there any in-universe reason for this discrepancy? Perhaps since he wants to play for Japan, he's better off with a Japanese surname? I think the school Kong played for was Tsujido, and this also seems relevant.

Answer 1

The keyword is in the (Japanese) naturalization.

Kong Wenge took a Japanese nationality by mean of naturalization. After naturalization, he needed to have a Japanese legal name.

From this article,

Do you have to take a Japanese name if you naturalize?

[...]

The simple answer to this question is YES, you do need to take a Japanese name.

The reality, however, is that a "Japanese name" is not necessarily what you are thinking. You have to follow the same rules that a Japanese parent has to follow when naming a baby... [...].

[...]. As you can see, some of us (like me) choose to write our existing names in Japanese characters. Others choose a more Japanese-sounding name that is similar in either sound or meaning to their original name, and others choose something that is altogether different from the name they were born with.

You do need to write your name in Japanese characters. This can include ひらがな (hiragana), カタカナ (katakana), 常用漢字 (jōyō kanji) (kanji for everyday use), and/or 人名用漢字 (jimmeiyō kanji) (kanji designated for use in names), [...]

^{(Emphasis mine)}

While 孔 (kō) is actually an acceptable kanji (it's inside kanji for everyday use), given the privilege to change his name, he chose 辻堂 (tsujido), probably to show his support to his high school.