







Slim Crazy Horse Leather Briefcase — Style I
Tax included. Shipping calculated at checkout
Pairs well with


Choose your work essentials for a slim outline. Genuine Leather Briefcase I.
Gather the documents and work essentials you need and head to work. Briefcase I combines Crazy Horse cowhide with a canvas lining. Choose between two slim sizes, large and small, according to what you carry each day.
Dimensions, materials and specifications
- Material: 100% genuine cowhide (Crazy Horse leather)
- Lining: canvas
- Country of origin: China
- Closure: zip
- Large size: 43 × 31 × 3 cm
- Small size: 38 × 28 × 3 cm
- Weight: 1.1 kg
- Strap: none
- Interior storage: slot pocket
- Interior storage: mobile phone pocket
- Interior storage: laptop divider
- Exterior storage: slit pocket
Choose between two sizes to suit your belongings
Which size, large or small, suits your work? Lay out your usual papers and notebooks and imagine what you will take. Choosing a bag size is also time to reconsider what you need for work. For those who want an outline suited to their own belongings.
Cowhide character for your working day
The material is 100% Crazy Horse cowhide. Enjoy its feel and shades in a bag for everyday work. Choose a material you appreciate not just in appearance but while packing and unpacking, too. With continued use, the sheen of frequently touched areas and a familiar feeling become increasingly personal.
Arrange interior and exterior storage in your own order
Inside are a slot pocket, mobile phone pocket and laptop divider. Use the outer slit pocket according to how often you take items in and out. For those who would rather give small items their own places than mix them with documents. Check device dimensions including cases against the storage dimensions.
For morning preparations before work
Check the day’s plans and put the necessary papers in the bag. Preparing in the order you will use things in a meeting can also help you picture the work ahead. Close the zip and set off—enjoy that brief gesture with a favourite bag. It suits days meeting people and days continuing familiar tasks alike.
Use it away, then return each item to its place
When working elsewhere, spread your work essentials on the desk and put them back one by one when finished. Even in a different location, familiar storage feels reassuringly known. For those who want preparing and tidying their belongings to be part of their working habits. No strap is included.
Your familiar bag for learning on days off
On days off, replace work documents with books and notebooks for yourself. Research an interest or organise what you have learned. Taking your everyday bag to different plans gives you more occasions to grow familiar with it in your life.
Enjoy the time after use, too
Empty the bag when you return home and take a look at the leather. Care for it with a soft cloth and prepare everything for tomorrow. Time spent using it becomes part of the shape you liked when you bought it. For those who want that kind of relationship with genuine leather belongings.
Familiar leather for tomorrow’s plans, too
For those who want to separate papers and small items, choose a slim bag to fit their belongings, or enjoy cowhide paired with canvas. Welcome Briefcase I as a piece you can grow close to, from everyday preparation to the end of the working day.
Colour transfer: precautions and care
Due to the nature of Crazy Horse leather, colour may transfer during use or storage. Take particular care when it touches light-coloured clothing or fabrics. Please note the following.
- Check that care products suit the material: Test leather sprays and similar products on an inconspicuous area before use.
- Regular maintenance: Check that leather oils or creams are suitable for the material and test on a hidden area first. Care does not completely prevent colour transfer.
- Storage after use: Store the bag in a well-ventilated place after use. Keeping it away from direct sunlight, heat and high humidity helps protect the leather from deterioration.
Notes about product information
- Colour differences: The photos show the actual product, but colours may vary under different lighting or on different screens.
- Texture differences: Cowhide texture varies slightly between areas. Thickness and texture may differ depending on the part of the hide. Please bear this in mind.
- Natural characteristics: Natural leather has its own texture and may show marks, folds, spots and vein patterns. These are characteristics of natural leather, not quality defects.
- Changes in smell: If the smell bothers you just after purchase, air the item in the shade in a well-ventilated place. The time needed for the smell to lessen varies between items.
Please read before purchasing
For details about delivery times and packaging, please see our Shopping Guide page via the link below.
Important information about delivery times and packaging



Small size










Large size



What Is Crazy Horse Leather?
Crazy horse leather is cowhide treated with oils and waxes to create a finish that changes in colour and surface character with use. Despite its name, it is not horse leather.
A finish that develops character
Bending or rubbing the surface can bring out lighter and darker areas. Areas that are handled frequently may develop a sheen, while creases and surface marks contribute to a patina over time. The way the finish changes depends on the item, how it is used and how it is cared for.
Natural leather also varies in grain, texture and colour. Product photographs show examples; lighting, screen settings and the individual piece of leather can affect its appearance.
How it differs from other materials
Check the material on each product page. A canvas bag with crazy horse leather details is not an all-leather bag. PU with a crazy horse-style appearance is synthetic leather, and needs different care from genuine cowhide.
Choosing a bag or wallet
Choose the shape, dimensions, weight and storage for what you plan to carry. Do not rely on a laptop’s screen size alone to judge fit; compare the device’s actual measurements and the thickness of any case. For a smaller accessory, check the length and thickness of the tools or items you want to store.
Moisture and colour transfer
The leather is not fully waterproof. Avoid heavy rain and prolonged wet conditions. Friction, perspiration and moisture can cause colour transfer, particularly onto light-coloured clothing and fabrics. A protective spray or conditioner cannot guarantee that colour transfer will stop.
Everyday care
- Wipe dust gently with a soft, dry cloth.
- If wet, blot away moisture and let the leather dry in the shade with good airflow.
- Avoid direct heat, sunlight and humid storage.
- Use care products suitable for the finish, following their instructions and testing on an inconspicuous area first. They may change the colour or texture.
- If a new item has a noticeable leather smell, let it air in a shaded, ventilated place. The time it takes to settle varies.
When to ask for help
Natural variation does not mean every problem is part of the material’s character. If you are concerned about damage, construction or another issue, contact cowmono with your order number and photographs.
Explore crazy horse leather bags and accessories or read our colour transfer and care guide.
Leather Colour Transfer and Care
Leather dyes and finishes can transfer onto clothing, furniture or other fabrics. Friction, moisture and perspiration can increase the risk. This can happen with new leather and does not always disappear after a fixed period of use.
Why colour transfer happens
Leather is a natural material, and finishes vary. Contact with damp fabric or repeated rubbing can move colour from the leather surface onto another material. Take particular care with light-coloured clothing, bag linings and furniture.
Taking care during use
Before first use, wipe the surface gently with a soft, dry cloth. Avoid prolonged contact with light-coloured fabrics, especially in wet or humid conditions. If the leather gets wet, blot moisture away and let it dry in the shade with airflow, away from heaters and direct sunlight.
Cleaning and storage
Choose care products suitable for the specific leather finish. Follow their instructions and test on an inconspicuous area first, since cleaners, oils, creams and sprays can change the colour or texture. Do not assume a care product will make the leather waterproof or prevent all colour transfer.
Store leather items in a dry, ventilated place away from direct sunlight, heat and humidity. Keep differently coloured leather and light fabrics from rubbing together during storage.
If you are concerned about a particular item, contact cowmono with your order number and photographs.
Shopping guide
Thank you for shopping with cowmono. Please read these notes before placing your order.
1. Shipping and delivery
cowmono simplifies its distribution process and reduces unnecessary distribution costs to offer a balance of materials, quality and price. Read more about cowmono.
After you order, we arrange dispatch from a warehouse overseas.
Your order → cowmono arranges dispatch → overseas warehouse → carrier transport → local delivery → you
Delivery times vary by destination. Check the information during checkout and our shipping policy. Busy periods at the warehouse, carrier arrangements and customs procedures can cause delays.
We email your tracking number after dispatch. Stock can change quickly for popular items; if an item becomes unavailable after your order, we may need to cancel it.
2. Cancelling an order
See our returns and refunds policy for cancellation information.
2-1. Return policy
Change-of-mind return requests within 14 days of delivery · Unused/unworn · Customer-paid return postage
- Before returning an item, email support@cowmono.com and use the return method specified by cowmono.
- Nothing in this policy limits your non-excludable statutory consumer rights, including any applicable cancellation or withdrawal rights and rights relating to faulty, damaged, or incorrect goods. The 14-day request period and unused/unworn condition apply only to our voluntary change-of-mind return policy and do not restrict those statutory rights. If you receive a faulty, damaged, or incorrect item, contact support@cowmono.com for information about the remedy available under applicable law. cowmono covers reasonable return costs where required by law.
- Orders placed before this update remain subject to the return terms in effect when the order was placed. Your statutory consumer rights remain unaffected.
- Estimated refund processing time: credit card or Paidy, about one week; convenience-store payment, bank transfer, QR payment or Pay-easy, up to one month. The store recommends credit card or Paidy for quicker refund processing.
3. Payment methods
The payment methods available for your order appear at checkout. Choose from the options shown there. The information below also explains payment services used in Japan; it does not mean that every service is available for every delivery country.
The store offers credit card payments through Shopify Payments and, where available, Paidy, prepaid payments at Japanese convenience stores, QR payments, Merpay, bank transfer and Pay-easy. If you do not use a credit card, choose an alternative offered at checkout.
Prepaid payments at Japanese convenience stores
The processing fee stated by the store is JPY 220, including Japanese tax. Supported stores are FamilyMart, Lawson, Ministop and Daily Yamazaki.
After completing your order, you are redirected to KOMOJU. Check the amount, enter the payment details and complete the payment steps. Payment is due within three days from the day after your order. We arrange dispatch in the order that payments are confirmed. An unpaid order is automatically cancelled after the deadline.
KOMOJU emails the payment number you need. If you use email filters, allow messages from @komoju.com and no-reply@komoju.com.
Pay-easy
The processing fee stated by the store is JPY 190. This prepaid service accepts payments through compatible bank ATMs or online banking. After ordering, follow KOMOJU's payment instructions and check the deadline shown on the payment screen or in the email. We arrange dispatch once payment is confirmed.
Paidy
Enter your email address and mobile number, then confirm the four-digit code sent by SMS. Purchases are generally combined into one payment in the following month.
The service information also describes a free upgrade to Paidy Plus, with monthly budgeting and three instalments without an instalment fee. Check current eligibility and terms directly with Paidy.
The payment methods and fees stated here are direct debit with no payment fee, convenience-store payment with a JPY 390 fee including Japanese tax, and bank transfer with a fee set by the bank.
QR payments with PayPay or au PAY
Register with PayPay or au PAY before use. These payments cannot be combined with another payment method.
Your order is not complete if more than five minutes pass after opening the payment page, or if cancellation or an error prevents confirmation. This also applies if you do not return correctly to the order completion page after payment. The payment is then cancelled, and any anticipated provider bonuses may be cancelled too. cowmono cannot restore those bonuses.
When scanning a QR code with the app, keep the page on your computer open until payment is complete. Private or incognito browsing is not supported for this payment. Check spending limits with PayPay.
For au PAY, you need to add funds to your au PAY balance. The limits stated here are JPY 300,000 per payment and JPY 500,000 per day.
Bank transfer
- Payment is made in advance. We begin arranging dispatch after confirming receipt.
- The account number differs for each order. Check it again even if you have ordered before.
- You pay any bank transfer fees.
- If payment is not confirmed by the deadline, the order is cancelled. A transfer made after the deadline cannot be accepted for the expired order.
- Transfer the exact amount. The payment rules described here do not provide for refunds of overpayments. Your non-excludable statutory rights remain unaffected.
Merpay
Merpay is a payment service within the Mercari app. Eligible users can pay with their balance, points or Merpay Smart Payments. Register in the Mercari app and set up Merpay before use.
Check details and the limits that apply to your settings with the provider. Contact Merpay about app operation, errors or passwords.
4. If your order confirmation has not arrived
Check the email address entered when ordering and your spam or junk folder.
5. Missed deliveries and incomplete addresses
If you miss a delivery, follow the carrier's notice to arrange redelivery. The carrier may be identified as YDH JAPAN or another delivery company.
An incorrect or incomplete address may lead to the parcel being returned. Parcels may be disposed of after the holding period expires. The rules described here do not provide for redelivery or a refund in that situation; your non-excludable statutory consumer rights remain unaffected.
Check your address, particularly the street number, before ordering and receive your parcel within the stated period. Repeated cancellations caused by prolonged absence or incomplete addresses may lead us to restrict the available payment methods.
6. Contact us
Use our contact form or email support@cowmono.com. We do not offer telephone support.
7. Other notes
- Stock can change quickly. If an item becomes unavailable after ordering or there is a dispatch problem, we will contact you by email.
- Colours may differ from the photographs because of lighting, surroundings and screen settings.
- Measurements are taken by hand; a variation of approximately 1 cm is possible.
- Natural leather can vary in colour and surface appearance and show natural markings. These individual features form part of the material's character.
About cowmono
cowmono is an online shop for bags, wallets and small accessories. Our selection includes crazy horse leather, other genuine leathers, canvas and PU designs, with different shapes and storage layouts for everyday use.
Choose by material and practical details
A bag should work with what you carry. Compare the materials, dimensions, weight and storage on each product page. Genuine leather, canvas and PU have different appearances and care needs; check the specifications for the item you select.
Direct shipping and simple packaging
Orders are dispatched from overseas warehouses in simple protective packaging. Packaging can differ by item and dispatch location. Dispatch and transit times depend on the product, destination and carrier, and customs processing can cause delays.
If you need an item for a particular date, contact us before ordering. Read our shopping guide for ordering and delivery information.
Explore the collection
Shop all products or learn more about crazy horse leather.
Shop with confidence
Our store does not retain full card numbers or security codes. Payment details are handled through Shopify and the relevant payment providers.
Connections are encrypted, and we review Shopify’s fraud analysis. We may request verification or cancel an order when necessary; this does not guarantee that all fraud can be prevented.
We manage and use personal information as needed to process orders and arrange delivery, and may share it with delivery and payment service providers for these purposes.
Payment options include cards, PayPal, Apple Pay and Google Pay, subject to availability at checkout.
Choose options









