Huge post incoming! Will post when I get home from work!
Manchukuo was set up specifically for Japanese interests and from the beginning, various members of the Japanese military, industrial investors, and civilian officials saw it as an opportunity to expand Japanese agricultural production, increase living space, and increase population growth.
The original creation of Manchukuo was almost completely an independent action by the Kwantung Army, against explicit orders to not do so by the Imperial General HQ and civilian government of Imperial Japan. It was originally conceptualized by Kwantung Army Lt Colonel Ishiwara Kanji, IJA Captain Toumiya Kaneou, and member of the Ministry of Colonial Affairs, Katou Kanji.
The idea was to solve both the overpopulation problem in the mainland islands as well as Japan's reliance on food imports (industrial population growth and concentration of the population swells in urban areas + feeding them all were a growing problem) by forcibly colonizing Manchuria during a time when Chinese influence in the region in general was waning. For this, the Kwantung Army organized and executed the Mukden Incident and subsequent invasion.
Afterwards, the government decided to support the Kwantung Army actions and thus led to official Imperial support for the Manchukuo nation as well as Imperial Japanese forces going on a campaign to pacify and subsequently occupying Manchukuo.
But it should be noted how divisive Manchukuo was. For example, civilian Prime Minister Inukai Tsuyoshi, a liberal progressive politician who strove to build a parliamentary government with the British as the model, was against recognizing Manchukuo. He was famously assassinated by the military faction in 1932.
Previous prime minister Takahashi Korekiyou was the Finance Minister in Inukai's cabinet. He proposed to reduce military spending and was against providing money and subsidies to a mass immigration plan to Manchukuo like the military faction wanted. He was assassinated in 1936.
The military faction as well as the imperialist industrialists were greatly in favor of Manchukuo and militant imperialism in general while the civilian government prior to the 2nd Sino-Japanese War were generally against it and were very wary of the growing influence of the military/industrialists.
Back to Manchukuo!
Once the pacification was complete with a whole puppet government, the Japanese government and Kwantung Army leaders decided that they would settle some 1 million households in Manchukuo over a 20 year period. This meant moving and settling 5 million people (Japanese estimates were 5 per household). Needless to say, this was a MASSIVE undertaking and was insanely optimistic by any estimate.
The government gave tons of privileges and deals to prospective farmers to try and convince them to move to Manchuria. Land was incredibly cheap and it was very much like frontiers in America. Claim some unsettled land, buy the land and pay the cost and fees with the local administration, and kablammo, you own whole acres, or rather chobu for the Japanese.
The subsidies offered were incredibly substantial. For example, in 1935, officials offered free transport to Manchukuo, up to ten chobu (~25 acres) for private ownership and even more for leasing land, as well as generous subsidies for contructing houses, infrastructure, and big write offs for the purchases of livestock, farming tools, machines, seeds, etc.
If farmers brought their families along, they would receive further cash allowances.
These incentives were incredibly large because the first five year plan involved a quota of 100,000 households (~500,000 people) to establish the first foothold in Manchukuo.
But of course, as we know today, the plan was a complete failure.
The first five year plan failed to meet 100,000 households. Initially only some 200,000 individual poineer farmers with no families arrived over a period of the first 5 year plan, with only a few thousand complete households. No where near the 100,000 households.
Why did the plan fail?
Firstly, many farmers and settlers were recruited into the military as war broke out in the Chinese mainland, so that greatly weakened the momentum of the settlement movement. This eventually left only women, children and the elderly on these settlements in Manchukuo, which we will revisit in a bit when we talk about what happened to Japanese settlers after the war.
Second, despite the many incentives as well as a great many appeals to nationalism and patriotism (settling in Manchuria was portrayed as furthering the cause to the Empire), it was still often seen as a risky, unsure move, particularly for those with families and farms.
Manchuria and Mongolia were seen as backwater, undeveloped areas and landowners with stakes in property in Japan were hard pressed to give up their land and homes for an uncertain future in the frontier. The government tried its best to advertise the grandness of the new land as well as the rich, fertile farmlands (which was true), trying to convince people that they could become big landowners there, but it wasn't that effective. Many were skeptical and there was no sense of Manchukuo being a place of 'making it big'.
The initial successes of the Manchukuo immigration movement was found in recruiting unemployed, landless poor in both the urban centers (crowded by those looking for jobs) and the displaced farmers who had been replaced by machines, had their land bought up by wealthy land owners and industrialists, or those who could not compete with the industrial scale production. Particularly in Nagano Prefecture, where many farmers had gone bankrupt after the period of the Great Depression, the program had great success, recruiting some 30,000 farmers for the initial waves of "Manchuri-Mongolia Reclamation Units" 満蒙開拓団.
The program found the most success in recruiting the disenfranchised who had little to no stakes in Japan and were eager for a chance to alleviate their unemployment, declining wages, and poor quality of life in the job scarce rural countryside.
These often single men with no family were recruited and organized into Pioneer Units and Armed Emigrant Corps. The reason why this sounds kind of militant is because it was.
Which brings us into our third reason, Manchukuo was very dangerous and violent.
Settlers went into Manchukuo armed because they knew that they would likely be fighting against bandits, Communists, Soviet forces, partisan anti-Japanese forces, and natives that still lived on fertile lands they wanted for themselves.
In fact, nearly 50% of initial settlements were placed along the Soviet border, with each being given specific military duties that they were responsible for, like perimeter defense, border watch, entrenchment, etc.
Even though the Kwantung Army had a large presence in Manchukuo, often conducting operations to 'pacify' the countryside as well as attack the local warlord and bandit strongholds, life was pretty dangerous for a Japanese settler. They could expect to be fighting fairly often, whether to protect their own personal property or being called up to defend the local settlement/area to supplement standing garrisons. And this is before the big call up to fight in the war in China proper.
It was so difficult to convince adult farmers to come that the Japanese government created the Youth Volunteer Army. It's name was later changed to the Manchurian-Mongolia Settlement Youth Volunteer Corps to be more 'welcoming'. The program recruited directly from age 15 to 18 year old's to do their service to the Empire and help pacify and settle Manchukuo. Their slogan was "hoe in the right hand, rifle in the left hand".
Casualty rates were high in certain areas (as high as 40% apparently for Ishikawa Prefecture's branch settlements in the frontier), especially as reprisal attacks on settlers became more and more common, especially with the abuses of the Kwantung Army, such as forcibly relocating farmers to less fertile land, forced labor, forced recruitment into the military, requisitioning of food and supplies from natives, pacification operations, etc. This became particularly dire as more and more fighting age men were recruited to fight in the war, leaving their women, children, and the elderly behind.
PART 2 BELOW