If you want to become a citizen of Taiwan, the following may offer information that will be helpful to you:
Many foreigners in Taiwan have residence in the form of an Alien Residence Card. This green colored card allows you to legally stay in Taiwan based on the fact that you have a legal job (employer is indicated on the card) or that you are married to a local.
To be a citizen of Taiwan means that you have an actual ROC ID card. With this, you can get phone numbers easily, own property, own a business, etc. To become a citizen, you must renounce your original citizenship. Your marital status has no effect on your status as a citizen of Taiwan.
Becoming a citizen gives you a lot of freedoms that you will not have otherwise. If you are married and your credit card, car, home, etc. are in your spouse's name. A divorce can be a severe disadvantage to you. This is eccentuated if children are involved, or if maybe you have moved and changed jobs many times.
To get Taiwan citizenship, you need to go to your District Office (Qu Gong Suo) and find the Household Registry Office. They will give you a list of things you need (written in Chinese). The requirements may vary and this post is biased by the process I personally went through myself. Luckily, mine was comparatively simple since I am single, no children and have kept the same job for 7 years.
You will need to have lived in Taiwan using an ARC for at least 5 years and have not been away from Taiwan for more than 180 days at a time. You will need to produce at least 7 forms of documents in order to complete this process. They are outlined as follows:
1. An entry/exit document.
2. A document from your employer(s) (Tzai Tze Tzen Ming).
3. Proof of residence (Ju Liu Tzen Ming).
4. Local police report with "no convictions". (Jin Tsa Ju Tzeng Ming).
5. A copy of your most recent tax report, if you are a legal worker.
6. Copies of your current ARC and passport.
7. A copy of your police report from your original country.
You will also need numerous passport-sized photos, so make sure they're good ones because these things seem to last forever.
The entry/exit document can be obtained by going to a Ministry of The Interior (MOI) office (bring your passport, ARC, and at least some cash--maybe $400). These exist in at least Taipiei, Taichung, and Kaohsiung. (Ask me for directions if you want to go to the Kaohsiung branch). The document from your employer--they should know what that is. (3) and (4) can be obtained from your local police station's foreign affairs office (a few hundred dollars' fees for those). (5) tax report--you should receive this from your employer in Jan or Feb of any year*. (6) Easy. (7) Difficult *.
* All of these documents can not be more than 60 days old, so it's very unlikely you could apply for citizenship in Jan or Feb of any year, as you have not yet received your most recent tax report from your employer.
* Your original-country police report needs to be at least A4 or (in the case of US) "Letter"-sized paper. This is because it will need a series of stamps. This document will have to have certain things done to it:
1 Send it back to your original country's Taiwan Economics and Cultural Office (TECO) and have them "authenticate it" (by putting a stamp on the back. The purpose of this stamp is to say "Yes, this is really from (your original) country). There is a fee (US$15 for the US) and you can negotiate postage options based on how much of a hurry you are in. TIP: You will need to make separate bank-draft checks for the processing fee and for the postage fee.
2. Upon receiving your report with the stamp on the back, you can save time by copying the front and giving that to a translation agency. They can work on that while you go for number three.
3. Take the original document to a Ministry of Foreign Affairs Office (MOFA). In Kaohsiung at least, these are in the same building. I can't say the same for Taipei, but I imagine the same is true. The MOFA stamp indicates that "the stamp from (your original country) is really a Taiwanese stamp."
4. The translation company will have to have it notarized. You can't take it yourself unless you translate it yourself. I learned this the hard way and it cost me an afternoon.
Last: Remember this process because you will need to do this again.
HOUSEHOLD REGISTRY OFFICE:
Take this back to that office along with all of your other documentation (don't forget a lot of pictures, your passport, and ARC). Their eagle eyes will scan it and if everything's OK, they'll send it off to the City office you live in and then to the MOI. They will eventually call you "in a month" (but it's actually 3 weeks) and tell you to come get your document. This is "preparation for ROC naturalization." (Zun Gui Hua Zhong Hua Min Guo Guo Ji Zheng Ming). This says that within a year, if you cancel your original citizenship, you will become an ROC national. This can act as a sort-of ID card, should you be stateless.
CANCELING YOUR CITIZENSHIP:
Do this at your orignal countrys' office in Taiwan. I was a US citizen and did this at AIT Kaohsiung and my story is posted under "Dual Nationality and Dual Citizenship". When you receive a document of cancellation of your original citizenship, you will have to go through the same process as your police report. Once you do this, give it to your local Household Registry Office and wait "a month" (not really--3 weeks) and you will receive your diploma-looking document that you are now a Taiwan national. However, not a citizen yet.
Take this back to the MOI office (or entry/exit office if you prefer) and fill out a form. You willl need to translate your parents' names into Chinese. This was a tough, time-consuming process for me. With much help from the friendly staff and loads of liquid paper, I finally got this done. They even made an extra copy for me, knowing that a year from then when I apply for my "real" ID card I'd need to write this the same way. In a week I got registered mail, went to my local police department, gave them the letter, they searched in a drawer and gave me my Taiwan-national, but not citizen card. I will carry this for a year.
Also, I was instructed to go to my *very* local police station and sign up for "dong ren Kou". This means that I virtuallly moved out of my house with an English name, turned around, and moved back in with a Chinese name. With this card, you need to do this every 6 months, so don't forget. (When I went, they were in shock for about 5 minutes before they agreed to do it for me. However, the officer I met was very friendly and filled out the whole thing for me.)
I'm at this point now. I'm a Taiwan national, but not yet a citizen. I have a card that says the equivalent of "Republic of China Taiwan Area Residence Card".
Forumosa's "Satellite TV" is a much better resource than I am for what happens after this process. If you're interested in this process and/or curious about the documents, tell me privately and give me your email and I will scan those and send them to you.
I want to hear what you think AND I want to help anyone as much as I can, so let's keep this going.