What are the REAL requirements for becoming a permanent resident in
Japan?

I am unmarried and I have lived and maintained an address (I have
moved several times) in Osaka for 5 (going on 6) consecutive years. I
worked as an English teacher for four years through the JET Programme,
and was unemployed for 3 months before securing a contract (renewable
yearly) at a company at which I have been employed for 1.5 years. I am
currently on a new 3 year working visa. I have also recently passed
the JLPT 1.

I know the immigration office guidelines are vague. I have checked
quite a few sites and realized that many, including debito.org, are
quick to exalt the benefits of being married. I don't think I should
get married for the express purpose of attaining permanent residency.
I don't think I should be expected to either. I've always enjoyed
supporting myself and enjoyed my freedom. If I am able to support
myself financially, I don't think attaining residency should be so
difficult.

The guidelines set by the Japanese immigration office are "guidelines"
and there seem to be examples of individuals who have attained
permanent residence status in less then 10 years. I would like to here
from unmarried permanent residents (of course I'd like to hear the
experiences of married individuals as well) and learn more about their
experiences with attaining permanent residency. While I understand the
good faith and stability arguments of granting permanent residency to
those who have been married to Japanese nationals, I feel obliged to
attain residency on "my own," without the pressure of having to get
married to be a permanent resident.

I would especially like to hear about what topics were used in the
essay (理由書）part of the application and what type of person you chose
to be your guarantor（保証人）.
I am hoping to complete my application within the next few months. It
will be interesting to see if I am eligible.

The current requirement for getting permanent residency status in
Japan for foreigners is located here in English:
http://www.immi-moj.go.jp/english/tetuduki/index.html

Examples of successful and unsuccessful applicants are provided here
(scroll down the page):
http://www.immi-moj.go.jp/english/tetuduki/index.html

The most significant being (note the asterisk and the note under (3)1
which begins with 'in principle'):

(2) The person has sufficient assets or ability to make an independent
living.
The person does not financially depend on someone in the society in
his daily life, and his/her assets or ability, etc. are assumed to
continue to provide him/her with a stable base of livelihood into the
future.
(3) The person’s permanent residence is regarded to be in accord with
the interests of Japan.
   1. In principle, the person has stayed in Japan for more than 10
years consecutively. It is also required that during his/her stay in
Japan the person has had work permit or the status of residence for
more than 5 years consecutively.
      ※ The requirements (1) and (2) above do not apply to spouses and
children of Japanese nationals, special permanent residents or
permanent residents, and requirement (2) does not apply for those who
have been recognized as refugees.

I can't wait to hear your comments.