According to the Public Offices Elections Law, exploiting this requirement by moving one’s residential registration to another municipality — just on paper — for the purpose of voting, while continuing to reside in an original municipality, is illegal.

But this kind of electoral fraud is a prevalent and deeply rooted problem in the Japanese electoral process.

So how is this sort of electoral fraud actually committed? Cases where a candidate or supporters ask relatives and friends living in other municipalities to move their registration to the candidate’s own address, or that of their electoral offices, are the most common. There are other obviously shady cases, such as one instance where 202 people were registered as ‘living’ at an address of only 240 square metres, or another instance where a large number of staff members ‘lived’ in a teppanyaki restaurant. There is one case where the massive influx of people into a municipality some months before election increased the municipality’s population by more than 10 per cent.

Why is this sort of electoral fraud possible? Not all municipalities hold their elections on the same day, making it is easy enough for someone to move their address from a municipality that doesn’t hold an election to another municipality that does. More importantly, the paperwork required to change one’s address is extremely simple in Japan. A required form must be submitted within 14 days of moving, but no proof of residence is required. It is even possible to ask someone else to submit the form on your behalf. In one reported case, an agent abused this procedure and submitted the change-of-address form for up to 128 people in a day.

Three months after submitting the paperwork, individuals are automatically given voting rights in the municipality where they moved in. Candidates are able to get a list of automatically registered voters (which is based on their residential registration) prior to the election. As a result, candidates can monitor whether their supporters actually change their addresses and sanction them if they do not.

Why would candidates go to such petty lengths to increase their number of votes? In Japanese municipal assembly elections, there is a high probability that a small number of votes could change the result. These elections use the single non-transferable voting system. Under this electoral system a large number of candidates compete with one another within the same district. As the entire municipality constitutes an at-large electoral district in a municipal assembly election, voters must often choose a single candidate from 10–100 candidates (depending on the size of municipality).

Under this system, the difference in total votes between candidates tends to be extremely small. It is not rare for the winning margin between an elected candidate and a losing candidate to be less than 10 votes. Generally speaking, the smaller the municipality size, the smaller this difference becomes — meaning that the incentive increases for candidates to try whatever means they can to gain additional votes.

Statistical analysis shows that the ‘shady’ cases reported in the media are just the tip of the iceberg.

Our analysis focused on municipal elections in 2003 and compared municipalities that held elections on 27 April 2003 and those that did not. We obtained municipality-level data of the number of people who moved into each municipality from January 2001 to December 2004, and looked at the increases and decreases in the reported number of ‘new’ residents compared to the same month from the previous year. We then compared these statistics between those municipalities with an election on 27 April 2003 and those without.

The number of people moving into municipalities with an election spiked at around January 2003, particularly in small municipalities. In order to vote on 27 April 2003, people would have to have moved their residential registration by around mid-January. So, it can be argued that the abnormally sharp increase in residential registrations in January 2003 was a result of people moving their registration in time to vote in the upcoming election.

The number of fraudulent residential registrations was on average around 10 people in municipalities with an assembly election (but without a mayoral election). In around 20 per cent of the municipalities investigated, the difference between the elected candidate with the least votes and the losing candidate with the most votes was within just 10 votes. So, the small number of fraudulent residential registrations we discovered was large enough to influence election results in many Japanese municipal elections.

These results may imply a dilemma regarding the design of the democratic system. One of the requirements of a healthy democracy is to ensure the political participation of as many people as possible. One way to encourage this is to make the processes and procedures to gain voting rights as simple as possible. Yet, if these procedures are too simple, the risk is that they encourage dishonest political participation through fraudulent residential registrations. This is indeed the case in Japan.

The big question now is: what kind of system would increase the participation of honest voters and at the same time prevent exploitation of the system?

Yusaku Horiuchi is Associate Professor in the Department of Government at Dartmouth College and holds the Mitsui Chair in the Study of Japan.

This article was translated by Jill Mowbray-Tsutsumi. A version of this article was first published in Japanese in Nikkei Business Online on 19 December 2011. This article first appeared in English here in the Australia and Japan in the Region forum, a publication of the Australia-Japan Research Centre.