Official

According to the official text "Chuo-ku Monoshiri Encyclopedia", Komakisha, located in Irifunecho, Kyobashi-ku (now Akashicho) in Meiji period, was a milk sales company run by Toshizo Niihara.
His eldest son is Ryunosuke Akutagawa, and Komakisha is also known as the birthplace of Ryunosuke.

If you look further, you can see that Komakisha itself started a ranch that Eiichi Shibusawa started with his friends in Sengokuhara in Hakone in 1879.
The relationship between Chuo-ku and Eiichi Shibusawa seems to be deeper than I expected.
(Click here for information on places related to Eiichi Shibusawa in Tokyo.)

However, on the local information board, Komakisha is written as a dairy cow ranch.
Was there a ranch in the Tsukiji settlement?
Below, I would like to compare and briefly consider the descriptions of Komakisha in the Kyobashi Library Local Archives and in the literature, papers, and websites viewed online.

Kanagawa Museum of Modern Literature “Ryunosuke Akutagawa Exhibition 100th Birthday” (Kanagawa Literature Promotion Association, 1992)
This exhibition material contains a picture of Tsukiji Reservoir (including Komakisha) at the time provided by the Yokohama Port Opening Museum, and the following commentary is provided.
"There were only three Western houses and hotels, and there were only three Japanese living. One of them was the Niihara family, which ran a milk sales business (Komakisha). " （p. 8）

Kyobashi Library, Chuo-ku, Tokyo, "Chuo-ku Year Meiji Bunka Hen" (Yaesu Printing Co., Ltd., first edition 1966, revised edition 1991)
"On March 1, 1892, Ryunosuke Akutagawa was born in Hachinoichi, Irifune-cho as the eldest son of Toshizo Niihara. My father had a ranch here since 2016 and ran a milk exploitation and sales company Komaki. " （p. 110）

Seiro Kawasaki “Birthplace of Ryunosuke Akutagawa”, “Literature” March and April 2004 issue (Iwanami Shoten, 2004)
Kawasaki, the author of the paper, discovered a drawing showing the building where Toshizo Niihara lived and ran Komaki-sha at the diplomatic historical museum of the Ministry of Foreign Affairs, while investigating the birthplace of Ryunosuke Akutagawa.
Among the drawings contained in the file entitled "Tokyo Foreign Residents' Relocation Expansion" (3.12.22) owned by the Ministry of Foreign Affairs' Diplomatic Archives, it is said that some of the drawings attached to the documents addressed to Foreign Minister Shigenobu Okuma and Minister of Foreign Affairs Aritomo Yamagata on July 7, 1888.
There are also drawings depicting Shinsakaemachi 7-chome and Irifunecho 8-chome, which are described as follows.
"The land and building of Toshizo Niihara was located in the northeast corner of Irifune 8-chome. Probably, the small building on the eastern end of the site, at the border of Shinsakaemachi 7-chome is the residence of Niihara (i.e., the birthplace of Ryunosuke Akutagawa), and the large building on the west side of the site is Komakisha, and Niihara has dairy cows here. It must have been producing and selling milk and butter. " （p. 186）

※Seiro Kawasaki "About the birthplace of Ryunosuke Akutagawa-Where is the site of Komakisha now?" Net Pinus 62, "Tsukiji Foreign Settlement" supplement (Yushodo Publishing, 2008).

Yasuyoshi Sekiguchi, "The Age of Ryunosuke Akutagawa" (Chikuma Shobo, 1999)
"Niihara worked at Giankusha Ranch in Hakone Sengokuhara, which was started by Eiichi Shibusawa and others, but in 1883, he became the ruler of Komakisha, a milk retailer with its head office, and at the time Ryunosuke Akutagawa was born (i.e. around 1892), the branch was moved to Naka Negishi, Shiba, and 1senya. （p. 5）

In addition, Son Ichiro Yokoyama, who joined the top management of the Imperial Hotel, which was opened in 1890 by a neighbor of Niihara, and after the opening of the hotel, Komakisha stored milk in the hotel, and Komakisha was built in 1883. At that time, there were not many Japanese people living in Shinsakaemachi 7-chome and Irifunecho 8-chome.

Chiaki Kitagawa “Tsukiji Akashicho Konjaku” (St. Luke International Hospital Chapel Committee, 1986)
"This area was a field where wildflowers grew, and there were about three Japanese houses. In addition to Komaki-sha, there was a car shop, and foreigners (living in settlements) were very useful. " "Komakisha continued until 1893, and 59.60 was said to have reached the hands of the American Church and became a building related to Rikkyo." （pp. 157-158）

Yoshiyuki Yazawa “Consideration of the Development and Progress of the Milk Business in Tokyo during the Meiji Period” (Japan Dairy and Dairy Industry History Study Group, 2013)
In 1888, Toshizo Niihara of Tsukiji, Kyobashi-ku reported that in 1888, two gelcy-type females and Hallstin (Horstein) from the United States were imported from the United States. 15 females and 2 males were imported. （p. 66）

Shinjuku Odori Shopping Street Promotion Association “History of Shinjuku Odori-Chapter 2: Shinjuku Odori in Meiji and Taisho eras”
A photo of the time is posted along with the commentary that "Komaki-sha was built in the late Meiji 20s".

Let's organize it in chronological order once.
1883 (Meiji 16): Komakisha was established at 8-chome Irifunecho
1888 (Meiji 21): Toshizo Niihara, import cattle from the United States
1892 (Meiji 25): The birth of Ryunosuke Akutagawa
1892-1896 (late Meiji 20s): Komaki-sha ranch in Shinjuku
1893 (Meiji 26): Toshizo Niihara, let go of Komaki-sha at 8-chome Irifune-cho and move the head office to 16 Shinsenza, Shiba-ku

Keeping in mind that cows were imported before a ranch was built in Shinjuku, and that the area around Komaki-sha at the time of its establishment was a field with wildflowers, dairy cows were kept in Tsukiji settlement, and milk was exploited. It is more likely that they were sold.
If you have a photo of the cow from Komakisha at the time, you can assert it, but this time I will only say that it is highly likely.
We will continue to investigate this matter, and when the spread of COVID-19 is stopped and we can go out with peace of mind, we would like to visit the site of Komaki House in Hakone and Sengokuhara.