Is it easier for people with some foreign nationalities to naturalize than others?

A better analogy would be the airport immigration lines
for citizens versus non-citizens.

Frequent readers may have looked at the countries, famous people, our authors & contributors, and the statistics and noticed that they see some (former) nationalities than others when it comes to acquiring Japanese nationality.

This naturally leads to the question, "Do we see more of people from one area or country naturalizing to Japanese than another because it's easier?"

The answer is: probably. However, the more general answer is that you see more of people of certain countries and locales naturalizing to Japanese due to deep connections made with that country due to geography (distance to Japan) and due to history: in Asian countries' cases, the connection to Japan during its Empire years. In the case of non-Asian cases (such as America), the connections America forged with Japan due to the Meiji Restoration and War and the post-economic revival that connected the two.

Until recently, the largest number of those naturalizing to Japan were those of Korean origin (either South Korea, North Korea, or the Korea that existed prior to the Korean War). You saw the greatest number of people naturalizing from this country because until recently when the Chinese population in Japan exceeded them, they were the largest group of legally non-Japanese in Japan.

Also, due to history, they often possessed the Status of Residence (在留資格 {zairyū shikaku}) of "Special Permanent Resident" (特別永住者 {tokubetsu eijūsha}). Those with a SPR SoR have an extra special simplified procedure for naturalizing, beyond the process that is called "simplified naturalization" (簡易帰化 {kan'i kika}). In particular, not only do SPRs not need to write a motive/reason for naturalizing (動機書 {dōkisho}), but they are except from meeting the arguably most difficult of the six conditions necessary for naturalizing:

4. Be able to make a living through his/her own assets or abilities, or through those of a spouse or of another relative who is making a living.

Additionally, people who come from countries that are still developing may have it easier because it may be impossible to obtain some of the paperwork normally required for naturalization. For example, in some African countries, there are no official and/or accurate government maintained offices of vital records, making it impossible to obtain reliable birth, marriage, and death certificates. In these cases, the case officer works with the candidate to find alternative ways to ascertain this information.

Additionally, although the letter of the law for the Japanese naturalization process requires one to lose your existing nationalities and be stateless prior to obtaining Japanese nationality via naturalization, some countries do not allow this (which is actually in violation of the Universal Declaration of Human Rights, Article 15). Many others (including Japan) will only allow you to lose your nationality once you have proven you have another nationality or are guaranteed to obtain one due to the UNHCR convention intended to reduce the amount of statelessness in the world. Furthermore, complications with the United States regarding those who attempt to lose their nationality for the purposes of tax avoidance have led to complicated distinctions in America between "relinquishment" and "renouncement" of U.S. nationality, which also affects when certain nationalities give up their nationality: before (which is supposed to be the norm) or after obtaining Japanese nationality.

However, I know of no case verified by third parties or sources where a person received special treatment or exemptions made, in the name of convenience, because of individual circumstances related to their nationality regarding following the procedures. Even Donald Keene had to go through a lot of paperwork for providing paperwork regarding his titles and academic achievements despite all the honors Keene has received from the Japanese government during his lifetime. Thus, do not expect that you will be able to successfully ask to "opt out" of providing family information because collecting the data is difficult if all the other people of your country are expected to provide it. Do not expect that they will let you opt out of losing your original nationality because it is financially disadvantageous to do so if other citizens from your country, some of whom are most definitely richer than you are, were required to do so.

In summary, Japan does not make requirements easier or harder due to your non-Japanese nationalities. However, gathering the paperwork may be harder or easier to do depending on the country you are from. And ironically, depending on your country, some paperwork or procedures may be legally impossible to obtain, which may, depending on the judgement of the Ministry of Justice, allow you to skip that portion of the process (or use an alternative process).