Just as every cultured Western household during the early 20th century was expected to have a piano in the parlor, almost all Japanese upper-class households, until well past World War II, had a koto. Training on this lovely 13-stringed zither, originally imported into Japan from China as part of the gagaku Imperial orchestra, was considered, along with proficiency in the tea ceremony, de rigueur for the well-bred young lady.

Until recently most women (and many men as well) had a familiarity with the instrument and the music. As recently as 30 years ago one often heard, walking through residential areas, the sonorous plunks of silken strings reverberating in the evening air.

Then came Yamaha. In the postwar economic boom, the company decided that pianos were the wave of the future and began mass-producing and mass-marketing them. Their ubiquitous music schools trained both piano students and teachers and insured that there would always be customers for their products.

Nationwide contests were set up and parents eagerly encouraged and prodded their children to practice, producing a high national level of proficiency and appreciation of piano music (along with overly motivated, neurotic young piano players).

Around the early '70s the market for pianos fell off, partly due to saturation and partly due to the ever-shrinking floor space of Japanese dwellings. Yamaha then concentrated on the smaller electric version of the piano, which in the West is called an electric organ but in Japan an Electone.

With the '80s came the synthesizer, an increasingly complicated piece of electronics which kept being reinvented, redeveloped, extended and marketed under new names into the '90s.

But what has happened to the koto? Traditions in Japan may seem overwhelmed and swallowed up by fashions or zealous marketing schemes, but rarely do they die out. In fact, the opposite is often the case. In an outpouring of sympathy for the underdog, a tradition which seems on the brink of extinction will often come back with a renewed vigor and re-establish itself.

There are signs that the koto, though never on the brink of extinction, is becoming popular again. The Ministry of Education, in a recent directive, announced that hogaku will become a mandatory subject in music-education classes from the year 2002. Long-neglected koto in both homes and schools are being dusted and tuned. Koto makers are discovering ways to make more affordable instruments, and there is a wide selection of learning tapes, CDs, videos and correspondence courses for students. Community cultural centers (like the Asahi Culture Center in Shinjuku and its other branches) offer lessons in koto, shakuhachi, nagauta, fue and other hogaku instruments in a relaxed atmosphere, away from the obligations and formalities of the strict iemoto guild system.

Still, the best way to approach koto music is through performances by great musicians. The end of October offers several opportunities.

Shoin Yamase is a highly respected performer of the Yamada style of koto playing. The Yamada style developed in conjunction with the rich theatrical traditions of Edo. As a result, the song is dramatic and visual, often using material adapted from the noh or kabuki theaters.

Yamase's program will include the Meiji Era koto piece "Miyako no Haru," composed by Shoin Yamase I in 1890 to celebrate the opening of the Tokyo School of Music (now part of Geidai, situated in Ueno Park) and premiered in the Sogakudo, which I wrote about in this column last month. "Miyako no Haru," although entirely in traditional style, reflects the upbeat optimism prevalent at the time.

Another piece she will perform, "Kogo no Kyoku," was composed by Yamada Kengyo (1757-1817), the founder of the Yamada style. The lyrics are taken from the episode of the Lady Kogo from "Tale of the Heike." The program will also include "Seki Heki no Fu," for shakuhachi and koto, composed by the great Yamada player and composer Kin'ichi Nakanoshima in 1934. The lyrics are a reworking of a well-known poem from Sung Dynasty China.

Yamada-style koto pieces offer a lively presentation, with numerous accompanists. Yamase will be supported by an array of fine performers, including two Living National Treasures: shakuhachi player Reibo Aoki and fue master Sanzaemon Takara.

Yamase Shoin Ensokai, 6:30 p.m. Oct. 26 at the National Theater Small Hall. Admission 4,000 yen. For information and reservations call Hogaku no Tomo-sha, (03) 3400-2806.

The other main style of koto playing is the Ikuta style. Although to a casual observer the two styles appear almost identical, there is a lot of difference in the detail, and, as in most of the Japanese performing arts, it is the detail which is most intriguing.

The most obvious visual difference between the two styles is the shape of the finger picks (Ikuta performers use square-tipped plectrums and Yamada performers oval ones) and the angle at which they sit to the instrument (Ikuta performers squarely facing the the koto, Yamada performers at a slight angle).

The repertoire also slightly differs, and the Ikuta genre usually places more emphasis on the highly developed instrumental interludes occurring between sections of the song, called tegoto. An upcoming performance by Ikuta veteran Miho Ashigaki will feature some traditional koto pieces, like "Yaegoromo," with highly developed tegoto, along with 20th-century koto pieces by Michio Miyagi and Kin'ichi Nakanoshima. This recital will commemorate Ashigaki's 50 years of koto playing.

Ashigaki Miho, Geireki Goju Shunen Kinen, 5 p.m. Oct. 28 at Shinjuku Asahi Seimei Hall, (03) 3342-3164, near the west exit of Shinjuku Station. Admission 5,000 yen, students 4,000 yen. For more information call Ashigaki, (03) 3389-5951.

A third recommended koto concert for this month focuses on contemporary hogaku music. Yuko Nomura is an accomplished performer based in Nagoya. Her concerts in Nagoya and Tokyo will feature her own compositions plus works by shakuhachi master Hozan Yamamoto, contemporary composer Bondai Fujii and her shakuhachi-player husband Hozan Nomura. She will play both the 13-stringed koto and the 17-stringed bass koto.

"Nomura Yuko: So, Jushichigen Recital," 6:30 p.m. Oct. 30 at Nagoya Seinen Bunka Center Artopia Hall, (052) 265-2088, a seven-minute walk from Sakae subway station on the Higashiyama Line; 6:30 p.m. Nov. 1 at Cross Tower Hall, (03) 3499-2887 (formerly Toho Seimei Hall), near Shibuya Station. Admission 3,000 yen in advance, 3,500 yen at the door. For information or reservations call Seigensha in Nagoya, (052) 241-2114 or in Tokyo, (03) 3714-1488.

The harsh climate of the Tsugaru Peninsula at the north end of Honshu produces hardy people and music with a vigorous character and a powerful beat unusual in Japanese music. Tonight at Penguin House in Koenji, (03) 3330-6294, 4-37-5 Koenji-Minami, Dai Yamamoto brings the bracing northern blast to Tokyo with hard-charging Tsugaru shamisen. Yamamoto loudly proclaims his independence from schools and factions and his improvisatory approach. Admission 1,600 yen (includes one drink).