All the different types of recorders can be pretty mind-boggling but Jodie Mesler’s youtube tutorial gives us some help as well as the Recorder Home Page.
The Japanese school recorders are available from department stores like Ito Yokado’s school supplies or stationery section, as well as Yamaha music stores but Yamaha is a major maker of professional music ensemble recorders.  If you are wanting the Yamaha recorders for ensemble use, you’d be wanting to look at Yamaha Tokyo Ginza Store (English page) or in Japanese – Yamaha’s mindboggling range of wooden recorders catalog or their plastic recorders catalog – or see a listing of the different types in English here.
商品写真YRN Yamaha recorder
As to which brand of recorder, the Recorder Home Page says:
” I particularly recommend instruments in the Yamaha 300 series, some of which have a woodgrain finish (rosewood or ebony). These are neo-baroque style recorders which have excellent intonation and tonal characteristics and are musically superior to any cheap wooden instrument. …. Plastic recorders modeled after eighteenth-century originals by Bressan (Zen-On), Haka (Aulos), Rottenburgh (Yamaha) and Stanesby (Zen-On) are suitable for solo work. They represent truly outstanding value and compare favourably with quality factory-made wooden recorders costing up to 10 times the price!

For ensemble use or for exploring the baroque chamber music repertoire factory-made wooden recorders by manufacturers such as Dolmetsch, Moeck, Mollenhauer, Küng and Roessler can offer excellent value for money and standards are rising constantly. Instruments in softer woods such as maple or pearwood can offer exceptional value for money. Be warned, cheap wooden recorders are often decidedly inferior to the plastic recorders noted above. By way of comparison, a Yamaha plastic alto recorder will cost around $50, a Moeck ‘Rottenburgh’ alto around $300. To get things into perspective, a high quality, custom-made recorder from the workshop of a master craftsman can cost in the range $1,500 to $4,000.”

Pentacorders, pentatonic recorders or pentatonic flutes

Speaking of the pentatonic recorder, it would to my mind, mean the Moeck pentacorder (see photo below)  which is popular with Waldorf or Steiner styled schools …

Moeck pentacorder
and if it is the Moeck pentacorder that you want, you can also order from Mercurius whose products are carried by Omocha Bako in Japan – pick from the catalog page the item you’re interested in, and then contact:
Kazuhiko Saito
Omocha Bako Co. Ltd.
26-12 Den Enchofu Minami
145 Tokyo Ota-Ku
phone: +81 337593387
fax: +81 337593279
eMail: info@omochabako.co.jp
URL: www.omochabako.co.jp
http://www.kunath.com/ sells the recorders online specially for the Steiner or Enki curriculum, but the shipping charges look  expensive.

Or another option is the Susato pentacorder  (see photo below)

Susato pentacorder

A Pentacorder is the easiest wind instrument to learn for people of any age. No thumb-hole is needed. Play two octaves with only two fingers of each hand! There is no other flute-instrument capable of doing that.  Tune books with a variety of pentatonic tunes and pentacorders can be purchased from Susato Pentacorders.
Somewhat confusing, there is also the pentatonic flute (which is sometimes interchangeably called the pentatonic recorder) — this would be Choroi pentatonic flute or recorder (contact info@choroi.org or order from An Siopa Beag).  Choroi instruments are designed to make pentatonic music in groups. The distinctive features of the Choroi flutes are their mild, light and flexible tone and a correspondingly simple, sculpted form. They are made of wood, each in one piece. The mellow tone makes them especially suitable for group playing. The Interval and Pentatonic Flutes were created to fill the need for high quality wind instruments in pedagogical work with younger children. With their simple scales they are ideal for improvisation, individually or in a group.
If you don’t want to order online, you might then want to try your luck with pentacorders with a large music instrumental store by carrying with you a print of the Moeck pentacorder picture at Moeck pentacorder and bring it along to the Yamaha Music Store or other music instrumental stores.
Recorder playing is an important part of the music curriculum in elementary schools of Japanese public schools (find out more about the music curriculum from “Globalisation and National Identity: A Reflection on the Japanese Music Curriculum” by Yuri Ishii et al. and the History of Recorder Playing in Japan (excerpted below from Recorder Home Page)
“The recorder was first introduced into Japan in the 16th century with early contacts with Europeans (Tada 1982). In 1549, Francisco Xavier came to Kagoshima in order to introduce Christianity, and many Jesuits followed him over the years bringing with them European instruments including flutes (ie recorders). However it was never very popular there. From 1639, the Tokugawa shogunate supressed Christianity and closed Japan to all foreign countries except Holland. The shogonate destroyed and burnt everything connected with Christanity, and Europrean music and musical instruments were no exception. Not until repeal of the law on national isolation in 1873 by the Meiji Restoration was Christianity and its attendant music and instruments permitted again. The recorder was not reintroduced until 1929 when a Japanese graduate of the University of Cambridge brought some recorders home, and in the 1930’s the German government sent some recorders and music as gifts to two Japanese professors. Shortly after WW II, an American resident in Japan, Leo Traynor (a virtuoso on the shakuhachi), provided an impetus to the introduction of the recorder. In 1948 it was adopted by the Ministry of Education’s new school music curriculum and makers began to manufacture plastic instruments. Initially instruments used and made in Japan employed so-called German fingering, but later the change was made to so-called English fingering. In 1961, the first performance using only Japanese recorder players was given of Bach’s Brandenburg Concerto 4. Subsequent visits by Hans-Martin Linde (1962), Gustav Scheck (1963), Frans Brüggen (1973), Carl Dolmetsch, Michael Vetter and Hans Maria Kneihs gave additional impetus to a growing interest in the recorder. From this time a number of Japanese students studied in Europe with these and other player/teachers. In 1975 four such students formed a recorder consort and won first prize in the international recorder contest at the Flanders Festival in Bruges.Today the recorder enjoys immense popularity in Japan at both amateur and professional level. There is an extensive repertoire of music for the instrument by Japanese composers (see Japanese Music for Recorder). And there are a number of Japanese makers of recorder including Aulos, Yuzuru Fukushima, Shigeharu Hirao, Kunito Kinoshita, Suzuki, Hiroyuki Takeyama, Toyama (manufacture Alouette, Aulos, Bel Canto, Elite & Robin plastic recorders), Jun Tsukada, Yamaha, and Zen-On.”