Most versions of Dieter Rams' ten principles you find online talk about Braun and the 606 shelving system. Inside our studio we use them differently: as a checklist before a proposal goes out, where each principle gets one line answering "what exactly am I doing about this one?" The principle we cannot answer is usually the one that comes back as rework later. And of the ten, the two that genuinely fight each other are Rule 5, unobtrusive, and Rule 9, environmentally friendly.
The short answer: Rule 5 pushes toward fewer materials, fewer joints and continuous surfaces so the product does not shout. Rule 9 pushes toward separable materials, modularity and structural zoning so the product can be recycled. They collide head-on on one decision: does the housing become a single closed shell, or something that can be opened? Our practice is to put both rules in the same column of the proposal and reconcile them before anyone starts sketching.
Where Rule 5 and Rule 9 actually collide
Start with the specific point of contact. Rule 5, unobtrusive, translates into appearance decisions: less visible parting line, fewer material types, fewer decorative parts, continuous transitions from one face to the next. Rule 9, environmentally friendly, translates into structure: different materials must be separable, the battery must be removable, fastening must be reversible rather than glued, packaging must be reduced.
Those two sets of actions meet on one question: snap fits or screws.
An all-snap housing looks the cleanest. No exposed screw holes, faces that meet almost seamlessly — Rule 5 scores well. But an all-snap housing is hard to open: separating the plastic parts requires destructive disassembly, and if the shell is PC+ABS with a metal bracket and a battery inside, the recycling end cannot separate the materials. Rule 9 loses.
Go all-screw instead and the environmental side is easy to open, but the screw holes either show or need cover caps, and both leave a visual stop on the surface. Rule 5 loses.
| Option | Appearance (Rule 5) | Disassembly (Rule 9) | Fits |
|---|---|---|---|
| All snap fits | Good, no exposed holes | Poor, destructive disassembly | Single material, no battery, whole-unit recycling at end of life |
| All screws with cover caps | Visible stopping points | Good, repeatedly serviceable | Contains battery, multiple materials, after-sales repair |
| Bottom snaps + hidden side screws | Good — the visible face stays clean | Medium — needs a tool but opens | Most small and mid-size consumer electronics |
On a power bank housing we used the third option: the top face is one continuous surface, the snaps sit on the bottom, four screws are recessed into the four bottom corners, and the parting line is placed at the start of the R corner where it is invisible at normal grip angles.
A useful rule of thumb: give the face the user looks at most to Rule 5, and the face the user never turns over in a year to Rule 9. The two rules do not each have to be satisfied on every surface — they can be divided by surface.
Rule 10 gets misread as "a minimalist style"
The short answer: when Rams says less, he means fewer distracting elements. To check whether a subtraction was done correctly, look at Rule 4, understandable — did you cut that too? Take the manual away and see whether a new user can still operate the main functions.
The classic counter-example is collapsing five physical buttons into a single touch area, which then requires the user to memorise single tap, double tap, three-second hold, eight-second hold and power-cycle restart. The manual grows from two pages to eight. The appearance score goes up; understandability falls much further.
"Less, but better" is the most quoted line and the most misunderstood. It means fewer distractions, not fewer functions and less structure. The test for a subtraction is whether it took Rule 4 down with it.
We have seen a real case: a small appliance cut five physical keys down to one touch area in the name of a minimal interface. The result required five interaction patterns — single tap, double tap, three-second hold, eight-second hold, and a power-cycle reset — and the manual went from two pages to eight. The appearance got cleaner, but a first-time user had to read the manual. Rule 4 lost more than Rule 5 gained.
The test for Rule 4 is crude but accurate: take the manual away and have someone who has never used the product complete each main function once, with no questions allowed. If they cannot, the rule is not met.
Indicator lights are where domestic products fail this most often. A single-colour LED encodes five or six meanings through steady, slow blink, fast blink, double blink and breathing patterns, and the user has no choice but to memorise them. Switching to two colours plus different positions carries the same information without asking anyone to remember a rhythm — an understandability fix at the appearance level, with no circuit change.
One more: before cutting buttons, count the user's genuinely high-frequency operations. If there are more than three, collapsing them into one touch area is digging your own pit.
Rule 6 is a hard constraint: no fake parting lines
The short answer: honest, for a designer, is an actionable list: no fake parting lines, no purely decorative ventilation slots, no plated plastic pretending to be metal, no two-shot moulding imitating a real material joint. What these have in common is that the cost moves to after-sales: the user's expectations, inferred from appearance, are not met, and complaints and returns follow.
Fake ventilation slots we have seen more than once. A row of decorative grooves on a plastic shell that reads as a vent grille but is sealed. After a long session the machine gets hot, the user's first thought is "the vents are blocked", and out comes a needle. Puncture it and water gets in; the after-sales team rules it user damage and the user disagrees. A few cents of decoration buys an argument nobody can settle.
Plated plastic pretending to be metal is the other one. The gloss can get close, but weight and thermal feel give it away the moment it is picked up. Worse is what happens when the plating wears: the product looks three years old after three months, and the user feels cheated. If the product is meant to be plastic, finish it as plastic — it is cheaper too.
On a blood pressure monitor we reworked the battery compartment three times, and one of those rounds was because the flap used a plated part: in the prototype the finish did not sit well with the body, and the plating was at risk of wearing at the hinge. Switching to the same matte plastic as the body actually improved the visual consistency.
Compressing the ten principles into one proposal checklist
We keep the ten as a table and walk it before every proposal. The point is not to answer "yes" but to answer "specifically how, this time" — and "which one am I overdoing".
| Principle | Ask yourself at proposal stage | Common way to overshoot |
|---|---|---|
| 1 Innovative | What exactly changed versus the previous generation? | Changing form for novelty, so users cannot find the familiar operation |
| 2 Useful | Does every feature map to a real function? | Piling on features until the main one is harder to use |
| 3 Aesthetic | What is the basis for the proportions, surfaces and CMF? | Sacrificing grip for looks, or pure decoration |
| 4 Understandable | With the manual gone, can a new user operate it? | Encoding too many meanings into one indicator light |
| 5 Unobtrusive | Which elements can go without losing function? | Reducing until there is no visual focus and it reads as unfinished |
| 6 Honest | Any decorative feature that misleads about performance? | Fake vents, fake parting lines, plated plastic as metal |
| 7 Long-lasting | Will this form still hold in three years? Are wear parts replaceable? | Chasing trendy colours and shapes, obsolete in a year |
| 8 Thorough | Are radii, chamfers, gaps and key feel held to one standard? | Gaps so small the process tolerances cannot hold them |
| 9 Environmentally friendly | Can battery, metal and different plastics be separated? | Sacrificing surface continuity and assembly efficiency for disassembly |
| 10 As little design as possible | Where is the line between removed and kept? | Cutting function as "noise" and making the manual thicker |
Rule 8, thorough, also has an easy way to overshoot. On a beauty device we first pushed a part gap to 0.1mm; on the drawing it looked clean. Talking to the mould shop, the combined injection and assembly tolerances could not hold it — at T0 the gap jumped between 0.15 and 0.2mm, which looked worse than a uniform 0.25mm. A gap is not better the smaller it gets; it should be a stable value inside the tolerances you can actually hold.
One last note on using the list: the ten are not meant to get equal effort. We normally identify the two or three this particular product will struggle with, satisfy those properly, and hold the line on the rest. Chasing full marks on all ten makes the programme expensive and slow, and the first three often undermine each other. Rule 10 is more useful as a final check than as a slogan at the start.
Questions we get most often
Q: Which of the ten principles conflict most often?
A: Rule 5, unobtrusive, and Rule 9, environmentally friendly, conflict most frequently; Rule 10, as little design as possible, and Rule 4, understandable, also fight regularly. The first pair concentrates on how the housing is joined: all snap fits look clean but cannot be opened, and a multi-material product cannot be separated at the recycling end; all screws open easily, but counterbores and cover caps break the continuity of the visible surface. The second pair concentrates on subtracting from the operation path — cutting buttons and cutting explanatory text tend to happen together, and once the user has to memorise operating logic, the line has been crossed.
Q: Why is "as little design as possible" not the same as a minimalist style?
A: What Rams means by less is fewer visual distractions and less unnecessary decoration; the target is noise, not function or necessary controls. Minimalism is a stylistic direction. The two are not on the same plane. The test is simple: after the subtraction, look at Rule 4. If the manual got thicker, or a first-time user needs a tutorial, what you removed was functional visibility — the wrong thing to cut.
Q: How do you verify that a product is "understandable"?
A: Put the manual away, find someone who has never used the product, and have them complete each main function once without asking questions, while you only observe. If they cannot, the principle is not met. The test needs to cover high-frequency operations, not just powering on. Indicator-light encoding is a common failure: a single-colour LED expressing five or six states through steady, slow blink, fast blink and double blink forces memorisation. Switching to two colours with different positions usually fixes it without a circuit change.
Q: What exactly does "honest design" forbid?
A: Three main categories: purely decorative fake functional features, material disguise, and surface treatments that mislead about performance. Fake ventilation slots, fake parting lines and plated plastic standing in for metal all belong here. The cost lands mostly in after-sales. Fake vents make users think overheating is a blocked vent, and some will probe it with a needle; puncture it and water gets in, and assigning responsibility becomes an argument. Plated plastic wears and discolours, so the product feels three months old after three months of use, and the gap in expectation shows up directly in complaints.
Q: Do all ten have to score full marks in a proposal?
A: No, and we would not recommend it. In practice we identify the two or three principles this product will struggle with and satisfy those properly, then hold the line on the rest. Chasing full marks on all ten makes a programme expensive and slow. Our process is to lay the ten out as a table with "specifically how, this time" and "which one might be overdone" on each row, and walk it before the proposal. Rule 10 is best kept for the final check, to confirm the earlier subtraction did not cut into functional visibility — as an opening slogan it tends to turn into a plain stylistic instruction.
Originally published by the Hezi Industrial Design team, based on our industrial design project practice in Dongguan. Learn more: Industrial design services
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