From
http://www.immigration.gov.tw/aspcode/L ... NodeID=142
第 三 條
原有戶籍國民具僑民身分之役齡男子,自返回國內之翌日起,屆滿一年時,依法辦理徵兵處理。
無戶籍國民具僑民身分之役齡男子,自返回國內初設戶籍登記之翌日起,屆滿一年時,依法辦理徵兵處理。
第 四 條
前條第一項及第二項屆滿一年之計算,以有下列情形之一者為準:
一、連續居住滿一年。
二、中華民國七十三年次以前出生之役齡男子,以居住逾四個月達三次者為準。
三、中華民國七十四年次以後出生之役齡男子,以曾有二年,每年一月一日至十
二月三十一日期間累積居住逾一百八十三日為準。
歸國僑民之役齡男子返國就學者,在符合緩徵條件之期間,不列入前項居住時間計算。
So, #4-3 seems to say those who are born in or after 1985 (I was mistaken earlier when I said 1975) will get into trouble of they stay over 183 days (1/1-12/31) for any two years. I think this was not an issue until now because they are now old enough to be drafted.
Again, make sure before you go so your life does not get interrupted unexpectedly.
(Hope the Chinese characters post and show OK.)
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Better yet, someone in another post posted the PDF link for the official translation:
http://www.nca.gov.tw/ENGLISH/law/Consc ... ese_07.pdf