U-shaped kitchen designs are also known as horseshoe shaped and are one of the most efficient and practical layouts available. Found in the 3 adjacent wall layout of cabinets, worksurfaces and/or appliances to form a U that encloses an area leaving a single space for exit and entry.

Aside from being the most economical use of space, it is also a favourite of both professionals and expert amateurs since it keeps to the principals of the perfect work triangle by minimizing distance between the three main work zones: sink, refrigerator, and oven.
Advantages of U-shaped kitchen designs
This particular layout has many benefits and will reward your choice on a daily basis.
Safety first. With a single entrance and exit to your workspace, there is less chance of collisions and accidents with other kitchen users. You also get to be focussed on the task at hand rather than be distracted by people wandering through.

Well defined areas. With 3 distinct areas to work, tasks will naturally find their own way to distribute themselves so segregation of tools and ingredients will follow an instinctive path to keep cooking, cleaning and preparation from overlapping.
More space. With all 3 walls to work with, storage and workspace are no longer at a premium. The advantages of this are many and varied but include; space for storing small appliances, workspace for meal preparation and room for multiple people to work.
Flexibility on kitchen size. So long as there is enough distance between each opposite work surface, the U-shaped kitchen arrangement will suit any size of room. As the kitchen gets to a certain size, an island is often included but the effect is the same.
Optimal Workflow. An enclosed design makes it easy to position the key work zones (cleaning, storage, cooking) in close proximity, adhering to the efficient work triangle.

Things to consider
Whilst there are many advantages to going U-shaped, there are always disadvantages to consider too.

Limited space. If the area you have to work with is particularly cramped, a U-shaped kitchen is very efficient but it can be quite claustrophobic when the gap between opposite worksurfaces is below 2 meters.
Awkward design. Corners equal complications and U-shaped designs have at least 2. Unlike galley kitchen designs, U-shaped have four corner cabinets (eye and knee level times two) and 2 worksurface joints. This can lead to increased costs and deep difficult to access cupboards.
Less open feel. Three-walled designs can feel more enclosed than an L-shaped or single-wall kitchen, which might be a drawback for those seeking an ultra-open-plan feel or who wish to socialise with guests in an adjacent living area.
Maximising light and space
A bit of forward planning can alleviate some of the negative points listed above and ensure your kitchen turns out to be perfect for your situation.

Link to a living space. In the example above one worktop doubles as a dining area.
Incorporate open shelving. Having wall mounted cabinets all the way round at eye-level will feel oppressive. Break it up a bit with glass fronted cabinets or open shelving.
Brighten with colour and finishes. In smaller U-shapes, opt for light colours and glossy finishes on cabinetry to reflect light and make the space feel larger and airier.
Consider corners creatively. Invest in corner storage solutions like carousels or magic corners to make every inch of the blind corners usable.
Use extra lighting. Standard kitchen strip lighting will only add to the gloom in shadowed areas, try under-cabinet lighting for work surfaces and ambient overhead lighting.

The U-shaped kitchen is a useful layout for anyone who values storage, organisation and an uninterrupted, efficient cooking experience. Mindful planning will transform this practical design into a stylish, custom-tailored culinary hub.