There is no cow comparable to a female cow, and thats not chauvinistic, its a fact. However, its true Kawamura Tokyo, and for those who dream beef, they dream of his steaks. These animals he uses are castrated males and so maybe my theory isn’t as I thought: https://mesubim.com/tag/kawamura/

During the end of each month in Japan, the availability and pricing of beef often fluctuate as wholesalers, distributors, and retailers adjust inventory levels and respond to changing demand. Restaurants may alter their purchasing patterns, and suppliers may focus on clearing or reallocating stock as part of their monthly inventory management. However, these market dynamics do not diminish the enthusiasm of consumers and professionals who continue to seek out the rare and highly prized cuts of beef.

Tomosankaku occupies a fascinating position in Japanese butchery because it combines characteristics that are normally found separately in other cuts. It offers much of the marbling associated with luxury Wagyu while maintaining a deeper and more pronounced beef flavor. Tomosankaku is one of the few muscles in the hindquarter that can combine the marbling of a premium loin cut with the deeper flavor of a working muscle. When roasted slowly to 52–54°C, it develops a texture that is both tender and expressive, with a richness that lingers without becoming heavy. This is why many Japanese butchers and Yakiniku specialists consider it one of the hidden treasures of the animal.

So what Makes Shintama Special: Enthusiasts remain willing to search for exceptional sections as as Tomosankaku, Marushin, Kamenoko, and other limited-production muscles that offer unique texture, flavor, and character. For many, the pursuit of these special cuts is part of the enjoyment of Japanese beef culture, where rarity, craftsmanship, and an appreciation for the individuality of each muscle are valued as much as the quality of the meat itself.

Shintama sits between the rump (rampu) and the round muscles in the hindquarter. It is one of the most versatile sections of the animal because it contains muscles with very different textures:

• Marushin (Shinshin): the most tender and refined lean muscle.
• Kamenoko: firmer, with deep beef flavor.
• Marukawa: balanced texture and flavor.
• Tomosankaku: the most marbled and luxurious muscle, often served at top yakiniku restaurants.

This is why many Japanese butchers consider Shintama one of the best cuts on the animal—it can provide the richness of premium Wagyu while retaining the clean, elegant flavor of lean beef. For many chefs, Tomosankaku from the Shintama is one of the hidden treasures of Japanese beef. The Tomosankaku is a premium, triangular cut of beef from the inner thigh (often referred to as the “tri-tip” in the USA. It is highly prized in Japanese yakiniku (barbecue) for its consistent marbling, robust beefy flavor, and melt-in-the-mouth texture.

Japanese-Style Roast Beef Shintama (Tomosankaku) is a preparation often used by Japanese beef specialists because it preserves the texture and natural flavor of the meat while allowing the marbling to gently render. And for those beef aficionados all Japanese Gyu is traceable showing the individual identification and slaughter numbers and below showing the cows whereabouts including its birth place: Ishigaki Island is the vibrant center of the Yaeyama archipelago, located in the far south of Okinawa Prefecture. With its turquoise seas, dramatic mountains, and rich cultural traditions, Ishigaki serves as both the gateway to the Yaeyama Islands.

The certificate below shows more details of the birthplace transfer and the cow was slaughtered the same day without causing it discomfort at the facility. But there is something most people do not know about the abattoir workers in Japan.

Burakumin Class:

Like many in the abattoir because of this profession and the Burakumin, Japan’s “untouchable” class. The Burakumin are a marginalized outcaste group in Japan, making up roughly 1.5 to 3 million people. Though legally emancipated in 1871, they still face societal prejudice and discrimination—particularly regarding marriage and employment—due to the historical stigma attached to their ancestry. Burakumin, meaning “hamlet people”, dates back to the feudal era. It originally referred to the segregated communities made up of labourers working in occupations that were considered impure or tainted by death, such as executioners, butchers and undertakers.

The lowest of these outcasts, known as Eta, meaning “abundance of filth”, could be killed with impunity by members of the Samurai if they had committed a crime. As recently as the mid-19th Century a magistrate is recorded as declaring that “an Eta is worth one seventh of an ordinary person”. Though generally considered offensive, the term Eta is still in use today. The caste system was abolished in 1871 along with the feudal system, yet barriers to their integration remained. Efforts were made in the 1960s to improve their lot by funding assimilation projects that improved housing and raise living standards, but despite this discrimination continued.

And, marbling is mythical for those who dream of A5, while connoisseurs who adore meat search for balance and not fat. The same way in sushi, akami is the preferred cut of professionals instead of the fatty oily cut of the belly o-toro. Thats not to say fatty isn’t important as it is however it is not all about the fatty content and more about the balance and one without the other is meaningless.

Tomosankaku is a cut located on the lower side of the cow’s inner thigh as seen below “inside round” classifying it, it is a part of thigh meat, which is representative of lean meat. Generally, when people hear thigh meat, many have an image of healthy meat with little fat and a bit tough. However, Tomosankaku vividly betrays that image in a good way.

How to handle:

• 2–3 kg Tomosankaku/Round
• 20g sea salt per kg of beef
• Freshly cracked black pepper
• 2 tbsp neutral oil
• 2 sprigs thyme or rosemary (optional)

Cooking Method:

Step 1: Temper the Beef

Remove from the refrigerator 5 hours before cooking, the center should still be cool, but the exterior should no longer be cold.

Step 2: Sear

Heat a heavy cast-iron pan, add some neutral oil and sear all sides thoroughly:

Step 3: Slow Roast

Preheat oven to:

100°C

Place the beef on a rack, and roast until the center reaches: the desired rare temperature 52 to 54°C

Roast Beef Sauce;

Combine:

• 100 ml soy sauce
• 100 ml sake
• 50 ml mirin
• 50 ml beef juices from the roast
• grated onion as desired

Simmer gently for 5 minutes, and strain and serve warm.