Editor | On 02, May 1998

Todd Williams
3M Corporation, St. Paul, MN
trwilliams@mmm.com

Ellen Domb
The TRIZ Institute, 190 N. Mountain Ave., Upland, CA 91786 USA
+1(909)949-0857 FAX +1(909)949-2968 ellendomb@compuserve.com

The 40 Principles of problem solving are among the oldest tools of TRIZ, and are used by most students of TRIZ when they first learn the basic TRIZ problem solving methods. (For a downloadable list of the 40 principles, with examples, see the article “Contradictions” in the July, 1997 issue of The TRIZ Journal.) They are included in all the commercial TRIZ-related software, and in the popular books available in English. (References 1,2,3,4,5,6)

The principles were developed during the initial patent research by H. Altshuller and his research colleagues, and provide methods, with examples, for solving large classes of inventive problems. The 40 principles themselves display both symmetry and asymmetry; that is, some of them are reversible (Principle 1, segmentation, and Principle 5, merging) and some are not (Principle 40, Use composite materials.)

The table below is a listing of the 40 principles, the opposite to each principle if one is obvious, and some examples of the opposite. We invite readers of this journal to contribute their own suggestions for completing the table. We have found that this is a useful exercise for classes in which people are learning the 40 principles for the first time.

We have speculated that the asymmetry of the 40 principles arose because these are principles for solving INVENTIVE problems, and the opposites may be the solutions for ordinary problems. (For example, use homogeneous materials is the opposite of use composite materials, but is not an inventive solution. Substitute fields for mechanical means is inventive, use mechanical means only is not, etc. ) We invite readers who participated in the research to write and let us know the history of the asymmetry of the 40 Principles. Please send you comments to editor@the-trizjournal.com

#	Principle	Opposite	Examples
1	segmentation	merging (#5), integration, agglomeration	integrate functions on a chip; fax, printer, copier in one device
2	taking out	merging (#5); adding in
3	local quality	universality (#6); global quality
4	asymmetry	symmetry; balance	two blade paddle; lever going to seesaw; symmetrize laser beam to get better focus for cutting
5	merging	segmentation (#1); separating
6	universality	local quality (#3); locality
7	nested doll	mutual exclusivity or mismatch	asymmetric telescoping shaft so it can be locked in place; incompatible shapes to help sorting or avoid mix-ups – like electrical plugs for different voltages
8	anti-weight	weight	add weight at one end of buoy to keep upright (also asymmetry); keel on sailboat; weighted bowling ball rotates for curve; heavier golf club head; heavier ax head, fishing sinker or lure
9	preliminary anti-action	preliminary action (#10); afterward anti-action	design polymer to biodegrade; design products for recycling
10	preliminary action	preliminary anti-action (#9); afterward action	delayed catalyst cure of resin; moisture or light cure; reusable shipping package; recyclable toner cartridge
11	beforehand cushioning	afterward cushioning	built-in indicator for failure
12	equipotentiality	increase potentiality	gravity feed conveyors in plant; electrophoresis
13	the other way round	internally contains opposites
14	spheroidality – curvature	linearity	put flat on bottom of blown bottles; make TV screens flat to improve image; convert turning motion of motor into linear conveyor motion
15	dynamics	statics	crash-worthy passenger compartment in auto; industry standard devices: plugs, bulbs; hose threads; magnetostrictive fluids
16	partial or excessive actions	this is its own opposite
17	another dimension	increase or decrease dimensionality	make a one-story rambler instead of two-story Victorian house; make flat Fresnel lens
18	mechanical vibration	remove vibration	air-bearing table for optics lab; vibration isolation dampers for buildings
19	periodic action	periodic inaction; continuous action (#20)
20	continuity of useful action	periodic action (#19); continuity of useful inaction
21	skipping	do at low speed to get combination of actions	cut plastic slowly to get heat to round the edges
22	blessing in disguise; turn lemons into lemonade	curse in disguise; turn sugar into vinegar	good tasting rat poison
23	feedback	lack of feedback; uncontrolled; positive feedback (feed forward)	random number generator; random noise generator for white noise in office
24	intermediary	remove intermediary; simplify; self-service (#25)	hammer with small head for small nails; agree on one file format; dish or pan with insulated handle so you don’t need a pot holder
25	self-service	single purpose device; intermediary (#24)	keep a key part separate so additional attention must be paid for safety – book matches vs kitchen matches
26	copying	avoid copies; use original
27	use cheap replacement objects	use expensive replacements, use expensive original	rechargeable batteries
28	substitution for mechanical means	substitution by mechanical means
29	pneumatics and hydraulics	mechanical	use a flywheel to store energy
30	flexible shells and thin films	rigid shells and thick slabs	make 2×4 wall instead of tent; hard-sided collapsible camper vs covered wagon
31	porous materials	impermeable materials	add wax coating on paper to make milk carton; add clay to paper to make better printing; put skin on foam to prevent water uptake; closed cell vs open cell foam
32	color changes	use monochrome systems, use negative images	use black & white instead of color to simplify image processing
33	homogeneity	heterogeneity	use softer rubber for tires for better traction; brake pads designed to wear; sacrificial anode for metal protection
34	discarding and recovering	this is its own opposite
35	parameter changes	parameter constancy	plastic food containers usable in oven; alcohol thermometer for low temps; silicone gaskets work over wide temperature range
36	phase transitions	phase stability
37	Thermal expansion	dimensional stability	match expansion coefficients of composite to avoid distortion
38	strong oxidants	strong reducers	use catalytic converter to reduce NOx using unburned HC; use hydrogen to crack petroleum components; use reducing atmosphere for specialized welding
39	Inert atmosphere	active atmosphere; presence of atmosphere; take away neutral parts; add active parts	remove water from product to make cheaper to ship; add magnetic particles to plastic to make microwave heatable
40	composite materials	monolithic materials	molded-in color so no painting is necessary

References:

1. The Invention Machine Co. TechOptimizer
2. H. Altshuller, Forty Principles, Translated by Lev Shulyak. Technical Innovation Center, Worcester, MA. 1998
3. H. Altov (Altshuller pseudonym), And Suddenly the Inventor Appeared, translated by Lev Shulyak, Technical Innovation Center, Worcester, MA. 1996
4. J. Terninko, A. Zusman, B. Zlotin, Step-by-Step TRIZ. Responsible Management, Durham, NH, 1997
5. E. Domb. “Contradictions” The TRIZ Journal, July, 1997, https://the-trizjournal.com
6. H. Altshuller. Creativity as an Exact Science, Translated by Anthony Williams. Gordon & Breach, NY. 1988