In Germany, citizenship is based on "blood"....jus sanguinis, it does not matter where you are born, if one parent is German. For many years, those who lived and work eg. Turks, were not allowed to become citizens, but that has been changed. Since Jan.1, 2000, if one parent is a permanent resident or if you have been residing there for over 18 years, and refugees and stateless persons of at least 6 years are eligible to apply. Speaking German is a requirement. One of the lugers at the Winter Olympics has a parent from Ghana.
In Japan, it is still very severely limited. A few applicants are accepted each year...a few hundred out of the 10,000 or so that apply each year. This means that the tens of thousands of Koreans and Chinese who have lived there for generations and speak the language, are still not eligible. You have to have lived there for more than 5 years and be over 20, be sane and have no criminal record, make an application and then be subjected to a very rigorous investigation.
In Canada on the other hand (USA, Britain etc have some of the same), you are eligible after being an legal immigrant for 3 years, or if you are born there (whether your parents are legal or not). It is a formality. This very enlightened approach took many years to be realised and Canada has benefited tremendously, especially given the aging of the population and the introduction of new ideas and money. The same for the USA. Over the past few weeks, there has been some concern over the decision of the Band Council in Kahnawake to expel about 25 people residing there who are non-natives. This is based on a 1984 law, that require residents to have at least four Mohawk great-grandparents. This race-based membership is as a result of the Indian Act and other race-based acts that give "rights and status" and define and allocate benefits based on blood-line and race eg. they are able to travel freely across the Canada/USA border and work in the United States without a green card as long as they can prove that they have 50% aboriginal blood. It is necessary for the band council to maintain a race-based membership list in order to get the many rights, benefits and monetary entitlements from the Federal government. Space is another factor in the limited territory/ reserve.
In the case of Saudi Arabia and Kuwait, restrictions are based on blood and religion. Children born to foreigners assume the parents nationality, irrespective of how long they have lived there. If a national is married to a non-national, citizenship is possible, but not if she is a Muslim and children are granted citizenship Non-muslims are not eligible for citizenship.
There is now a debate is Israel on this issue. The Law of the Return allows Jews to get automatic citizenship and many have taken advantage of this especially after the collapse of the Soviet Union....Minister Lieberman is an example of this. The Netanyahu government want to pass a law denying citizenship to children born there to non citizens and to deport them. This means that these children, many of whom have lived there from birth, and who speak and write Hebrew would have to leave the country. Israel was created as a Jewish state, only for Jews and there is concern about the population (about 85% are Jews). This law, if it is passed would be harsh and cruel. These children would be uprooted from the only home they know (most of their parents were brought there to take the jobs of Palestinians after the "uprising", when the Palestinians who were doing the low-paying jobs were barred fro Israel). These deportations would be inhuman, and hopefully something can be done to avert them.