According to the community-based Shonai Nippo, on August 20, 2019, a local review meeting of the "Taro Production Promotion Project Conference" launched last year led by Yamagata Prefecture was held at Sakanobe Shinden, Sakata City. It seems It seems that producers, JAs, and distributors throughout the prefecture learned about a new initiative to cultivate "Wase Yamato Taro" in the sand dunes during the imoni season and harvest it from around the end of August. The project meeting was launched in May 2018 under the initiative of the prefecture, including mass retailers, food manufacturers, wholesale markets, JAs, and municipalities. While imoni has spread as a representative food culture of this prefecture, the harvest season for taro produced in the prefecture seems to be from late September to October. For this reason, especially at the beginning of the Imonikai season, a large amount of Imoni from outside the prefecture, such as Kyushu, is sold in large quantities, and it seems that the aim is to expand production in the situation where the Imoni produced in the prefecture does not fully meet the market needs. I have also heard that prefectural institutions are taking the lead in experimental research in various parts of the prefecture.
Quick sleeves style overview, a handy reference chart by Edo-lover Nadeshico Rin :D You can see from left to right, top to bottom:
Hirosode 広袖 - wide sleeves opened on their full lenght (cuff sometimes closed by drawstring). Inspired by Chinese attires, they started to be used by Japanese nobles during Nara era. Those can be found on court attires such as hô 袍, kariginu 狩衣, suikan 水干, hitatare 直垂, etc
Makisode 巻袖 - work clothes used by men and women alike, worn by farmers, fishermen etc. Sleeves are cut diagonally offering freedom of mouvement.
Zenimarusode 銭丸袖 - lit. “round coin” sleeve, a man style popular in second half of Edo period. Name come from the fact round part of the sleeves was made using shimonsen coins.
Tetsubôsode 鉄砲袖 - “gun barrel” sleeve, work clothes worn by men from Meiji period. Note the underarm gusset for freedom of mouvement.
Furisode 振袖 - long dangling sleeves, which became popular in early Edo period and got longer and longer as time went by. In the past, those sleeves were worn both by girls and boys (before their mariage/genpuku ceremonies). This style is now mainly worn by girls+young women.
Tomesode 留袖 - “cut” sleeves, style worn by married women during Edo. Name comes from the fact it was customary to shorten one’s furisode sleeves when married. This style is now the sleeve style found on women kimono
Tsutsusode 筒袖 - tight tubular sleeves, work clothes worn by men and women alike since Kofun period. Tightness means there is no tamoto 袂 (”pocket”/drop part of a kimono sleeve).
Funazokosode 舟底袖 - “hull” sleeve, a work clothes style found on men and women clothes. The lower part is nicely rounded like the bottom of a boat.
Genrokusode 元禄袖 - Genroku round sleeve. Early 20th brought back some Genroku era fashion including this sleeve style (compare with squarer tomesode).