At JR Tokyo Station one day at 10 p.m., a Filipino family of five boarded an overnight bus bound for Kyoto. Having started their vacation in Osaka, they had made their way to the capital by the same means and were now on their way back to Western Japan.
During their 10 days in Japan, they would not stay at hotel even once.
The whole trip was made using a combination of overnight buses and private lodgings, thereby keeping expenses to a minimum.
One family member said she can happily get a good night's sleep, even on bus. The Tokyo-Osaka route can cost as little as 3,900 yen ($34.4) with Tokyo-based operator Willer Alliance.
Comfortable bus seats have become a popular choice for a growing number of foreign visitors eager to save on accommodation. The number using Willer Alliance in 2016 jumped almost four-fold from 2011 to 130,000 people.
The idea of sleep-travelling has even paved the way for new businesses.
Tokyo-based company Revolator is an Airbnb-style camper-sharing service, where people can rent campervans from private owners, which is attracting increasing numbers of budget-conscious tourists.
A group of nine Singaporeans last autumn used Revolator for a whistle-stop tour taking in Tokyo; Mount Fuji; Takayama in central Japan; the nearby Kamikochi highlands; and the Kansai region. After an action-packed 10 days, they returned to the capital.
Renting a camper can cost anything from about 7,500 yen to 30,000 yen per day on weekdays. Sharing the vehicle among six people brings even the most expensive option down to a very reasonable 5,000 yen per person.
Revolator has teamed up with igloo, a company based in Kamakura, near Tokyo, that runs a website promoting Japan tourism to foreigners and is also hoping to install a rental counter at Haneda Airport.
Cruises are another popular way of combining travel and accommodation costs.
On Jan. 13 at 9 a.m., 3,000 or so Chinese tourists were seen disembarking the Sapphire Princess at Hakata Port on the southern island of Kyushu. The 290-meter ship has everything you would expect from an upmarket hotel, including a spa, a gym and even a movie theater.
More cruise ships calls in at Hakata than any other port in Japan. In 2016, 328 cruise ships docked there, up 27% year-on-year, making it the gateway to Japan for about 1.7 million people.
During the off-season, cruise packages sometimes go for as little as 33,000 yen, making it a popular way to see the country.
Japanese airports are also providing an unlikely source of accommodation for the seriously budget-minded.
Kansai International Airport in Osaka at midnight on a January weekend had approximately 40 people in the 24-hour rest area.
A Thai woman, together with four family members, said they had just arrived on an overnight flight and were chatting about their upcoming 10-day trip. The family planned to spend the night in the airport.
Half the people there were wrapped up in light blue blankets provided free by the airport. According to the operator, so many people sleep at the airport that they often run out of blankets late at night.
A slightly unnerving statistic has emerged regarding foreign tourists to Japan: the total number of nights spent in accommodation is not increasing at the same pace as their actual numbers.
Oddly, the former is now smaller than the latter.
The total number of overnight stays is calculated simply by multiplying the number of visitors by the number of nights they stay. Thus, the number of stays will logically be larger than the number of tourists.
That trend was borne out by data from the Japan National Tourism Organization and the Japan Tourism Agency until last spring, when it unexpectedly reversed.
Data from other sources confirmed the change.
According to data compiled by the Nikkei, average room occupancy at major hotels in Tokyo last February declined for the first time in 11 months. In 2015, room rates at hotels around Japan rose by an average of more than 10%. The falling numbers have been attributed to the yen further strengthened on the back of Brexit.
So where do all the tourists disappear to at night?
Put simply, the statistics do not track every single type of accommodation. Stays at hotels and inns, for example, are covered, while private homestays and lodgings are not.
Yuji Nitta and Hiroyasu Oda contributed to this report