And I'm asking here because I dont speak Japanese fluently haha
Now I understand - Just seems funny when I read the initial post - someone from Tokyo needs to ask about bonsai?????
The new photo shows a different colour so much more like white pine and, yes, goyomatsu is white pine.
I think it is a little too top heavy for the current height and trunk thickness. Bonsai is all about proportion. Trying to grow something that looks like a natural old tree. So far this one is tall and skinny with a big cluster of foliage near the top. If you wanted to keep this tree as a small bonsai the top would need to be reduced.
However, what it looks like now is irrelevant because you want to change it to a larger tree size. That means growing it. Again, you always have a choice. You can keep it in small pots (just pot up a size each year or so) and it will grow and develop slowly so plan on a 20-50 year development program OR you can put the tree into a larger pot or into the ground somewhere and forget about it being bonsai for a few years. It will grow faster and you may achieve your goal in 5-10 years.
There is no one way to develop bonsai. So much depends on how you grow the tree, what facilities are available and your side goals during the process (maybe you want to keep it looking bonsai like during the transition).
A few things to be aware of, especially as you do not seem to know much about bonsai:
Pines do not live long when kept indoors. They need an outside position where they get plenty of sun to stay healthy.
Small pots are quite hard to maintain. It will need water at least twice a day in summer but too much water can also kill it.
Pines require special pruning and maintenance to keep them looking good.
We feed and water our bonsai to keep them healthy. That means they grow. That means we need to trim and prune to maintain a neat tree shape.
You have definitely picked one of the more difficult species for a beginner at bonsai.
How long are you in Tokyo and where is home? Do you plan to take this tree if/when you leave Japan?