Hatsumōdë is the first visit to a jinja (or Buddhist temple, but normally jinja) of the New Year. In one use, it simply refers to a person’s first visit in a year, no matter when it happens. The most common use these days, however, is to refer to the custom of visiting a jinja in the first three days of the New Year (or maybe a few days later if you are away). This is an extremely popular custom; the estimates I have seen are that about 80% of Japanese people do it, and I find that plausible, or maybe even a bit low. A lot of people perform their hatsumōdë during the night, and even at small jinja people start queueing half an hour or so before midnight. It is common for jinja to mark midnight by striking a taiko (Japanese drum), and to open the prayer hall at that point so that people can pay their respects.
Meiji Jingū in Tokyo gets the highest number of visitors of any single institution, and this year it reported 3,180,000 visitors in the first three days of the year. The report in Jinja Shinpō also commented that the number of foreign visitors to Meiji Jingū has significantly increased in recent years, and that, at hatsumōdë this year, the number of foreigners wearing kimono was striking.
On the other hand Jingū, in Ise, reported 490,000 visitors. That may not sound so impressive, given that it is said to be the most important jinja in Japan; why does Meiji Jingū get so many more? The answer is that Meiji Jingū is in the centre of Tokyo, where 35 million people have easy access by public transport; there is a railway and metro station just outside the entrance. On the other hand, the total population of Ise city was, according to the city’s website, 128,800. Thus, while 10% of the population of Tokyo went to Meiji Jingū, which is impressive, the visitors to Jingū numbered four times the population of the city. The nearest large city, Nagoya, is over an hour by express train, so people who visited Jingū for hatsumōdë were making a real effort.
The custom of hatsumōdë has roots going back almost a thousand years, to a New Year jinja visit performed by the first shogun, Minamoto no Yoritomo. It has, however, only become really popular in living memory. The older priests at my local jinja can remember when the night of New Year was very quiet, and now they have to hire security people to manage the crowds. As almost all the visitors make at least a small offering, and many make offerings for omamori or hamaya (lucky arrows), the hatumōdë visits have become very important to the financial stability of many jinja. I suspect that a lot of priests pray for good weather over the New Year.