The Nintendo Switch "Master Kase" Sling Bag - Product Development Story - Kiwee

Bag Design - Master Kase Sling Bag - Nintendo Switch


Let's explore the bag design story behind the Master Kase but before we start let's give praise where due. The Nintendo Switch is a magnificent machine in its own right but holding it up while playing for long periods of time and having no tables to set it up. Before we decided  to make the Master Kase we would take out our consoles and  play games just like this. Has this ever been you?

When we had the idea for the Master Kase during an online meeting, we weren't sure how many people actually had the same issues with game play as awe did and actually take their consoles outside to play, rather than just staying at home in their living rooms or in front of their computers. It seemed rare to find people in their 20's and 30's among our friends who still played Switch games.

 To validate the real needs of users, we summarized a few scenarios in which we ourselves would play games while on the go. We then went to several gaming forums we frequently visited and asked if these scenarios were indeed in demand.


 PLAY IN CABINS (Metro, Train or Airplane)


CAFÉs, BARS or at a McDonald’s

PLAY OUTSIDE (waiting rooms or parks with no available tables) 

After we asked around, we found that some people DID play on their Nintendo Switches outside. We even got a few hard-core players. One carried 3 consoles out every time, including a Nintendo Switch, a 3DS, and a 2DS, while another one carried a pair of Switch consoles as well as a pro controller and a PS5 controller, for different types of games.

In this process, we identified two core problems that this bag needed to address:

A.  Efficient storage and organization of the Switch console, along with essential accessories like Joy-Cons or Pro controllers.

B. Easy access to the gaming console and accessories, allowing for immediate gameplay wherever you are. 

With these key objectives in mind, we embarked on designing a solution that would seamlessly meet these needs.

Bag Design: The Balance Weight Challenge.

After several rounds of sketching, Rachel's (our designer) , began systematically experimenting with different overall structural designs. For example, she explored a single-shoulder bag with side pockets like the one shown below. One side would accommodate the console, while the other side would hold various accessories.

While this type of structural design made it convenient to store the Switch console, Rachel soon discovered that many users only played with the console itself and did not use additional controllers. Additionally, when the backpack had relatively empty space and only stored the Switch console without other items, including the structure shown in the previous image, many bag designs would cause the console compartment to continuously sway and hit the body when the user walked or jogged due to an imbalance in weight distribution.

 To address this issue, Rachel went back to the drawing board and sought a more balanced and stable solution that would accommodate both the console and the users' comfort during movement.

(Testing different structural designs for the console compartment) 

So, Rachel made up her mind. There would be a separate pre-molded hard shell compartment to store the Switch Console. So that this shell could protect its screen and joy cons properly, and reduce the risk of the joy sticks drifting.

Then she put the Switch console and its compartment and put it together to make a 500 gram object. This aim was for the bag to always stay stable and weight-balanced during its usage.


(A first version of the backpack model based on a dedicated hard-shell console compartment)

After repeated testing of several models, Rachel finally completed the initial structural design of the Master Kase, taking into consideration proper weight distribution and a dedicated hard-shell console compartment. The independent console compartment is placed at the bottom of the bag, while the upper portion serves as an accessory storage compartment. 

With this design, whether the bag contains the Switch console or only the console compartment is used, the overall bag remains lightweight and comfortable to carry. 

The best solution comes in steps - Protection + collapse dilemma.

Once the design concept for the bag's main structure was confirmed, the next step was to focus on the accessory storage solution.

 Thanks to our initial user interviews, we decided in the beginning that, the accessory compartment should be an open space, an open space with basic protection. On top of it, we decided to design add-on protection solutions for PRO gamers, to store and protect their gears.


This approach gives users the flexibility to decide what they want to include in the bag. Everyday essentials like a power bank or a water bottle can be easily placed inside. For digital accessories such as PS5 controllers, mirrorless cameras, headphones, or hi-fi music players, an additional protective structure with segmented compartments can be used, similar to how camera lens or drone accessories are stored. This design allows for efficient organization and easy access to different accessories. 

By providing customizable storage options, users can tailor the bag to their specific needs. Whether they need a compact and lightweight configuration or extra protection for delicate equipment, the Master Kase can adapt accordingly. This versatile approach ensures that the bag remains functional and convenient for a variety of users and their unique accessory requirements. 

Since most camera lenses are cylindrical, while controllers, joy-cons, and other gears are so diverse in shape and size,  plus she believed this solution should also protect joysticks, Rachel realized that the traditional camera bag solution would not work. Thus, Rachel began testing different storage solutions for various accessories individually.

She firstly made some plastic cases with a 3D printer. While this approach indeed provided an almost perfect protection for various accessories, it would require a different hard shell for each accessory. It would also involve the traditional method of removing the accessory storage box from the backpack, similar to the nesting doll concept. This significantly reduced the efficiency of using the accessories in a portable state. 

Taking such a convoluted approach did not align with our initial intention of balancing convenience and protection in the design. Then she tested a collapsible model to store several major controllers, starting with paper mockups.

After prototyping different customized solutions, practical testing was conducted to evaluate their usability and effectiveness.

The Main Challenge

The main challenge arose from the inherent contradiction between a collapsible storage structure and an emphasis on stability in the protective design. Rachel made multiple adjustments to the protective shell structure, attempting to secure the position of controllers and other accessories through precise fits. However, achieving simultaneous protection for the front joysticks and side L and R buttons proved to be difficult. Moreover, employing such complex assembly solutions could potentially discourage many users, as they might feel overwhelmed by the intricacy involved. In the words of prospective users, "Why does this new product have to test my intelligence?" 

Therefore, our goal was to minimize the learning curve associated with the design, ensuring that users can effortlessly and intuitively use the product without feeling overwhelmed or frustrated. 

Finally, on a mild morning, Rachel thought of the arc supporting structure in ancient Chinese buildings.

Since applying direct pressure did not seem to work, could she create a suspended space using curved panels? By utilizing an arch-shaped structure, the bag could bear the weight while avoiding contact with the protruding joysticks. 

If we are shooting an animation or documentary someday to record this design, this instant revelation moment will be pretty much presented this way. 

Rachel later said, "Those first tryouts are to complex. When you don’t think through and rush to a design solution, it often ends up in a complex design.The more you get closer to its principle, a better chance you will achieve a more appropriate design."

In most cases, it would be a less-is-more design.

Subsequent iterations of the structural design progressed smoothly, like sailing downstream. After a few minor adjustments, the final Zhaozhou Bridge-inspired accessory storage panel solution called the Arc Organizer emerged. It effectively balanced the needs of accommodating and protecting various accessories while ensuring quick and easy access to them. 

You could even store your gears according to your own priority, and store your most-used item on top for easy access.


 With the completion of the bag's main structure, accessory compartments, and the arc organizer, the design was now well-rounded and nearly finalized.


Everything needs to pass a durability test before its production. Once the appearance and structural design of the bag were completed, the next step was to ensure its durability and sturdiness. 

For sling bags, especially for gear protection sling bags, there is no general standard available. So we normally design our own test method and standard according to the product’s usage scenarios. Then we discuss with our manufacturer on which material and supporting structure we should apply to make those standards passed. 

Here are some of the tests that we did on the Master Kase sling bag:

Test 1
Could joysticks could be touched by mistake during usage, with or without joystick grips on.


@wearekiwee The arc organizer in action. Your joysticks and more stay protected while in the Master Kase. #masterkase #kiwee #nintendoswitch #gamingcontroller #nintendoswitcholed #nintendogamingbag ♬ original sound - Kiwee

 Test 2

The loading capacity of the shoulder strap as well as the structure stability of the pre-molded console compartment.

Test 3
To test the loading capacity of the hand strap.

Test 4
To test the fatigue resistance of the fasteners on the Arc Organizers.

 Designing and successfully passing all these tests was indeed a relief for us. because It meant, the Master Kase sling bag would stay in good shape during ones daily usage, till Nintendo launches its next generation console, no matter how many years it might take but we're hopeful. 


This is the design story of our very first game console bag, though it‘s more like an interminable development log. We do wish users could enjoy their beloved games more with this bag. May great games be with you. 

By the way, we will keep rocking the development of awesome bags and accessories for portable gaming devices. If you've got any cool ideas for features you'd like to share with us, or if you have any products you're using right now that you wanna vent about, come join our Facebook group

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