I did the Working Holiday and im german, so im gonna say something here.
Getting a teaching job will be hard (as everyone said) but not impossible. I did not work as a teacher.
I did get around before (1 year Australia) and i did bring more money than most travellers. Than i got lucky twice to work once work for these guys
JAPAN TRENDS – LIVE FROM TOKYO | Marketing, Lifestyle, Fashion, Gadgets and Product Innovations (the boss is german) and once find another job. Sadly the pay was just enough to life, so think good about doing this and bring enough money to survive for most of the time. I´d say an absolut minimun of 1 million yen for the year if you want to be sure. You can always bring money back.
In Tokyo you might get information or jobs fitting your skills here
Japan Association for Working Holiday Makers .
This is the governmet institution that is there to help people on a working holiday visa. There are few germans doing this year, i remember reading of around 200 visas beeing issued a year to German citycens but more to people from Australia or South Korea meaning you will be special and it will be harder to get a job.
What is essential for doing this and making it an enjoyable year is that you have to plan a bit. How much money will i need? Do i want to go to school to learn the language a bit more (i did 5 weeks in Tokyo). Where do i want to go? What kind of job is possible? How do i keep contact with home, mobile phones,....
The problem is that most people in the forum are teaching and never heard of the WHV, so they might tell you something very different from what i will tell you.
So, if you can make clear questions i can help you here or with pm, but i will need more information from you. I live really cheap for the year but lets just say you smoke and i don´t, that can make a difference.
But to answer the topic: If you are lucky you can work in a Restaurant, Conbini,.... but you will either need connections, good language skills or luck.
The
Japan Association for Working Holiday Makers will be helpfull, however don´t rely just on that
You can get jobs in Roppongi working for bars or trying to get people into clubs, however 90% of this jobs are not legal (even with your visa)
With the WHV your not supposed to have a job before you get there. Check out this video
YouTube - How to Get a Japanese Working Holiday Visa to get a better idea what the visa is supposed to be used for.
You could always try to do private english lessons, but this will be quite a bit of work and more difficult than if you´d be a native speaker.
There is also woofing in Japan
.: WWOOF Japan :. wich will not pay any money but you can work for accomodation and food.
You can write here or with pm if you have more questions.