The old Bible of thousands of FG wannabes for the past 20 years, "JOBS in JAPAN" and most others likeHow to Land Jobs in Japan advice to come here cold and semi-illegal to find a job.
Most J-companies do NOT wanna hire a Pig-in-Poke. The Bad-Case scenerio
is it's gonna take you 3 months to find job and more than $5-10K to get
your own squat, phone, fidge, etc. (The Good-Case scenerio is it's
gonna take you 3 weeks and $1,200). Please note many major Japanese
companies will not sponsor visas (your soon-to-be-bucho is forced to privately).
YIKES! Come to think of it, most of the long-term gaijin on the the FG
Forum came here under some sponsorship such as job transfer, Japanese
education, martial arts, JET, etc. I got headhunted here but I was told
to "wait" for 3-4 months. I scrapped and scammed as an illegal worker
in a bunch shitty jobs and then had to do the Korean visa run on my own
and at my own expense to get my work visa. It was DAMN TOUGH and I ran
out of money ($3,500 spent in 9 weeks). Without leeching off my Judo
sensai and a friendly mama-san who frequently gave me "taxi money" I
would never have "made it".
BOTTOM LINE: Go for it.