Firstly, please try to write with grammatically correct sentences as you are hard to understand.
If we look at the year 2020, then it is likely that China would have a GDP of 20 trillion versus 7-8 trillion for Japan.
Say they both spent around 2% of their GDP on defence, China would spend 400 billion and Japan would spend 150 billion. Now we must take into account that things will be cheaper in China due to the fact that China will order larger numbers of equipment and prices would still be cheaper due to cheaper labour costs. So if we increase by 50% to take this into account, then China will spend 600 billion versus 150 billion for Japan.
So China has a defence budget that is in effect 4 times the size of Japan and the gap would be getting wider over time as the Chinese economy would still be growing much quicker.
China does not need to spend more than 2% of it's GDP to become a superpower over the next 10-15 years and be in a position to be realistically able to invade the Japanese mainland, while at the same time defending it's borders.
Lol my grammar...well I had already said I don't proof read or spell check, so sue me.
I feel comfy enough to just say it as it is, it wasn't't anything formal as if I am publishing an article here, I believe I had 5 article out by the way, why would I need to put in effort to format my sentence?
Beside, yours grammar ain't very good anyway, seems like you have no right to judge me to begin with
Still, my point is, China being 30 times the size with Japan, I would consider it to be a failure if China just out perform 4 times with their budget.
You need a larger force to defend your land if you have a larger piece of land, if China is 3000% in size, and even if we say Japan is 200% capable to defend their own, you are looking at a force about 10 to 15 times the size of JDF in order for China to put enough troop on their own land. And then you can start talking about sparing force for other activities.
If indeed as you say, china would put in 2% at defence budget, that is no where remotely enough to have a totally secure China, even if they will have a 20 trillions GDP that's merely 400 billions, Chinese defence equipment is cheap, but not as cheap as you think
And I almost felt down the floor laughing when you say China can invade Japanese mainland in 10-15 years time...lol really gold moment.
US today, with 10 Aircraft carrier and 200 advance surface ship and 2 millions troop and a 650 billions budget cannot even remotely invade Japan main islands, may be it's ok if we are looking at Okinawa action again? Then perhaps we can pull it off, but Nippon home island? Lol seriously?
Do you know each country can only afford to sea lift and air lift portion of their military for oversea operation, for US, that number is 17%. and US have the most landing ship/assault ship/troop ship and Air transport by far than any military in the world. Looking at China and their equipment, I would give them 9% and that's already a very generous figure...
The supply line between China and Japan to the closest point is 350km, and no land route. You are talking about invading a peer to near peer with no absolute air superiority and naval superiority with a bad lifting ability, unless in 15 or 20 years of time Chinese can learn how to teleport, otherwise there are virtually no chance for china to invade Japanese homeland
Let me give you a few historic figure.
In peleliu, US lost 10000 dead or wounded from a nest 30,000 invading force, while Japanese have barely 10,000 plus change in the island
In Okinawa, US have a peak strength of 280,000 troop and lost 50,000-60,000 killed and wounded against 120,000 Japanese troop
In Iwojima, US had 76,000 forces in it where the Japanese defending with 22000 in the end we lost 20,000 dead or wounded.
If we were to invade Tokyo, we would have expected 1 millions lost and wounded.
All that was historical figure and in WW2, unless China have about 10 million spate people to die or wounded for the clause, china have no chance invading Japanese homeland