Expert Help Needed regarding to Wai Chou passport

Legal Dual Nationality
1

Forgive me if this was posted before, but I couldnt find one that answers my question.

My friend was born in Taiwan but he moved to the States since he was 8yrs old. He is now a US citizen but also holds a ROC passport but he told me its different, its called Wai Chou something. We will be going to Taiwan in a few weeks and he was thinking of using the ROC passport for entering and leaving Taiwan, but the thing is he is 22 yrs old and my question is will the ROC gov. refuse to let him leave Taiwan because of drafting requirements even though he has a US passport? I was also told that if you use ROC passport entering Taiwan you cannot use another foreign passport for exit?
Also will showing two passports at the airport immigration be a problem or Taiwan authorities wont care at all?

2

How long will he be staying in Taiwan for?

3

One week.

4

If he’s 22, he was born around 1986. In that case, he will be restricted from leaving Taiwan, if he stayed over 183 days per calendar year for two separate years. This applies whether he uses his Chinese Overseas passport or U.S. passport.

When leaving Taiwan during conscription years (19-36) with a Taiwan Overseas passport, he probably needs to request permission, which just means a trip to the National Immigration Agency. It’s a bit of a hassle for such a short stay.

If he does not have a specific purpose for using the Taiwan passport (ie moving houkou back to Taiwan.), he should just use his U.S. passport.