The entrance fee is about $8, and it's BYO towel and toiletries.
There is just one very large communal bath (gender separated of course), with about 20 wash stations around the edge. Some of the taps don't work, but an elderly lady, the only other bather here, points me in the direction of one that does.
Once cleansed, and taking in the surroundings from the comfort of the 40C dark mineral water bath, it's perfectly plausible to assume that little has changed at this onsen since it opened back in 1957.
The steamy bathroom has a massive height, perhaps 8m up to the ceiling, and the air is thick with humidity.
Layers of aquamarine-coloured paint peel from a pipe that runs overhead.
In the centre of the space two massive orb-style lights are suspended on heavy chains, like full moons glowing on a misty night. The glass brick walls that filter the light from outside are thick with dust.
Come here if: You want a quiet, old-style onsen experience. It's not flash at all, but has its own charm.
OOEDO ONSEN MONOGATARI
Onsen theme park, Odaiba
Billed as Japan's first and only "onsen theme park", Ooedo Onsen Monogatari is designed to take you back to the Edo period in Japan's history. A large temple-styled facade marks the entrance, where customers receive a cotton ukata (robe) for wearing in the common areas.
Before proceeding to the bathing area, there is a large indoor entertainment precinct that represents a traditional Edo-era village.
It's lined with food and beer outlets, souvenir shops and fairground-style game stalls, and the entrance fee is about $22.
Men and women then separate to their respective bathing areas, which offer a very good selection of indoor and outdoor pools with mineral-rich waters.
The baths are modern, attractive and tasteful, with temperatures ranging up to 42C.
Choose from the social indoor 100-person bath, or the quieter Kogane-no-Yu bath with its amber coloured water. Outdoors offers large stone pools and traditional wooden tubs for one or two people.
Men and women can relax together (wearing ukatas) in another outdoor garden area, featuring a footbath styled as a wending stream, with the option of having little fish nibble dead skin from your feet - novel, and ticklish.
Come here if: The novelty value appeals. It's hard to tell whether I'm more grateful this is the "first" onsen theme park or that it's the "only" one. Best experienced with a group of friends.
SPA LAQUA
Mega spa in the megatropolis
Spa LaQua is Tokyo's best-known "super spa" complex and is simply about one thing - indulgent relaxation. Spread over five levels, it offers an astounding range of spa, relaxation, treatment and dining options.
Basic entry costs about $29, with many optional extras. Everything you need is provided, from shampoo and towels to complimentary skin care products.
The salty waters of the Koishikawa hot springs, sourced 1700m below the city, flow through the beautiful bathing complex, with a wonderful array of blissful indoor and open air baths, saunas and a steam room. It is divine.
The open air baths at LaQua are fed by the famed Koishikawa hot springs, deep below the city. Photo / Getty Images
Inspired by healing treatments from places including Bali, Germany and Korea, you are invited to try a selection of low (40C) and ultra-low (5C) temperature saunas.
There's even a colour therapy sauna, where you can change the colour of the illuminated walls to suit your mood.
Fifteen massage and treatment rooms offer everything from an oriental head spa and an oxygen capsule to a Hawaiian lomi lomi massage.
If you need a break between spas, saunas and steaming, you can choose from four relaxation lounges where you can nap or watch TV. LaQua also has five stylish dining options.
Come here if: You are looking for the ultimate urban sanctuary. Spa LaQua caters to your every relaxation need.
CHECKLIST
Getting there: Air New Zealand has daily flights to Tokyo.
Further information: See japanguide.com.
The writer flew to Japan courtesy of Air New Zealand.
