40 Inventive Principles for resolving
technical contradictions

Genrich Altshuller discovered forty patterns of inventive solutions, known as 40
Inventive Principles. (TRIZ – Theory of Inventive Problem Solving).
The analysis of several thousand patents led to the conclusion that inventive tasks and
technical contradictions could be solved by a limited number of basic principles.
These principles were produced after analyzing over 40,000 inventions. They can resolve many technical contradictions without compromise and are useful of TRIZ creativity tools in a variety of problem-solving.
Already in 1956, 5 Principles were proposed, 18 Principles were developed in 1959, and in 1964 a system including 31 methods was proposed.
Only in 1971 was the development of a complete system including 40 Principles, which were presented in a small work:
Altshuller G.S. The main principles of eliminating technical contradictions in solving inventive problems. – Baku: Ganjlik, 1971. – 52 p.
After that, the system of 40 techniques was improved, and its options were published in the book:
Altshuller G.S. Algorithm of Invention. – Moscow: Moscowskiy Rabochy, 1973.
Altshuller G.S. Creativity as an exact science. Theory of solving inventive problems. – Moscow: Sovietskoe radio, 1979.
Search for new ideas: technology and inventive solutions / G.S. Altshuller, B.L. Zlotin, A.V. Zusman, V.I. Filatov. – Chisinau: Cartya Moldovenienasca, 1989.
Althsuller G.S., Zlotin B.L., Zusman A.V., Filatov V.I. Search for new ideas: from insight to technology (Theory and practise of inventive problem solving), Kishinev: Kartya Moldovenyaska Publishing House, 1989.
There are a number of modifications of Inventive Principles. V. Petrov performed a comparative analysis of these principles in his book:
V. Petrov History of invention principles development. Information materials. Tel Aviv, 2006 – 73 p.
Many of the principles have two, three sub-principles. Multiple examples of application for each principle are also accumulated for illustration.

Different formats for the 40 Inventive Principles were developed:
1. 40 Inventive Principles by G.S. Altshuller
2. 40 Inventive Principles by Oxford Creativity
3. 40 Inventive Principles by Karen Tate and Ellen Domb

40 Inventive Principles

In: Genrich Altshuller. The Innovation Algorithm: TRIZ, Systematic Innovation
and Technical Creativity. Worcester, Mass. : Technical Innovation Center, Inc., 1999.

1. Segmentation

a.Divide an object into independent parts.
b.Make an object sectional (for easy assembly or disassembly).
c. Increase the degree of an object’s segmentation.
Example: A tire that consists of 12 independent sections

2. Extraction

(Extracting, Retrieving, Removing)
a.Extract the “disturbing” part or property from an object.
b.Extract only the necessary part or property from an object.
Example: The collision of birds and airplanes can result in airplane crashes, and consequent casualties. There are many U.S. patents for methods to scare birds away from airport areas —mechanical scarecrows, chemical diffusion, etc. The best was the loud playing of tape recordings of frightened birds. Here, the bird’s voices were separated from the birds. This solution is quite unusual, but perfectly supports the principle of Extraction.

3. Local Quality

a.Transition fromhomogeneous to heterogeneous structure of an object or outside environment (action).
b.Different parts of an object should carry out different functions.
c. Each part of an object should be placed under conditions that are most
favorable for its operation.

4. Asymmetry

a.Replace symmetrical form(s) with asymmetrical form(s).
b.If an object is already asymmetrical, increase its degree of asymmetry.
Example: The outer section of an asymmetrical tire is made from stronger material to withstand impact when colliding with curbs.

5. Consolidation

a.Consolidate in space homogeneous objects, or objects destined for
contiguous operations.
b.Consolidate in time homogeneous or contiguous operations.
Example: An underwater rescue device for bringing people who are trapped in an air bubble of a sunken ship to the surface with the help of helmets. This device is different because it has two-or-three helmets, with hoses and fittings for connecting to valves mounted on the diving suits allowing for the regulation of air supplied to helmets. This invention improves the efficiency of rescue work.

6. Universality

a.An object can perform several different functions; therefore, other
elements can be removed.
Example: In Japan, the possibility of building an oil tanker that contained a refinery was considered. The idea for the project was to refine crude oil during transportation to its destination.

7. Nesting (Matrioshka)

a.One object is placed inside another.
That object is placed inside a third one. And so on . . .
b.An object passes through a cavity in another object.

8. Counterweight

a.Compensate for the weight of an object by combining it with another
object that provides a lifting force.
b.Compensate for the weight of an object with aerodynamic or
hydrodynamic forces influenced by the outside environment.

9. Prior Counteraction

a.Preload countertension to an object to compensate excessive and
undesirable stress.

10. Prior Action

a.Perform required changes to an object completely or partially in advance.
b.Place objects in advance so that they can go into action immediately from
the most convenient location.
Example: A method for removing a plaster cast by using a wire handsaw. This method is different because it consists of a blade inserted into a plastic tube that is then placed inside the plaster cast while the cast is being applied.
Because of this, the cast is cut from the inside out, without harming the patient’s skin. This method prevents trauma, and makes removal of the cast easy.

11. Cushion in Advance

a.Compensate for the relatively low reliability of an object with emergency
measures prepared in advance.
A method to prevent forest fires from spreading by planting barrier strips made of plants.
This method is different because it introduces chemicals, or biologically assimilated fertilizers that slow combustion, into the soil. This promotes the development of fire resistance properties in plants.

12. Equipotentiality

a.Change the condition of the work in such a way that it will not require
lifting or lowering an object.

13. Do It in Reverse

a.Instead of the direct action dictated by a problem, implement an opposite
action (i.e., cooling instead of heating).
b.Make the movable part of an object, or outside environment, stationary —
and stationary part moveable.
c. Turn an object upside-down.

14. Spheroidality

a.Replace linear parts with curved parts, flat surfaces with spherical
surfaces, and cube shapes with ball shapes.
b.Use rollers, balls, spirals.
c. Replace linear motion with rotational
motion; utilize centrifugal force.

15. Dynamicity

a.Characteristics of an object or outside environment, must be altered to
provide optimal performance at each stage of an operation.
b.If an object is immobile, make it mobile. Make it interchangeable.
c. Divide an object into elements capable of changing their position
relative to each other.

16. Partial or Excessive Action

a.If it is difficult to obtain 100% of a
desired effect, achieve more or less of the desired effect.

17. Transition Into a New Dimension

a.Transition one-dimensional movement, or placement, of objects into twodimensional; two-dimensional to threedimensional, etc.
b.Utilize multi-level composition of objects.
c. Incline an object, or place it on its side.
d.Utilize the opposite side of a given surface.
e.Project optical lines onto neighboring areas, or onto the reverse side, of an
object.

18. Mechanical Vibration

a.Utilize oscillation.
b.If oscillation exists, increase its frequency to ultrasonic.
c. Use the frequency of resonance.
d.Replace mechanical vibrations with piezo-vibrations.
e.Use ultrasonic vibrations in conjunction with an electromagnetic field.

19. Periodic Action

a.Replace a continuous action with a
periodic one (impulse).
b.If the action is already periodic,
change its frequency.
c. Use pauses between impulses to provide additional action.

20. Continuity of Useful Action

a.Carry out an action without a break.
All parts of the object should constantly operate at full capacity.
b.Remove idle and intermediate motion.
c. Replace “back-and-forth” motion with a rotating one.

21. Rushing Through

a.Perform harmful and hazardous operations at a very high speed.
E[ample:During the unloading of a log carrier, it is tilted by a special ship. To unload all cargo into the water, the carrier must be tilted at an angle which is too high and unsafe. This new method offers a smaller tilting angle through the use of a jerking action. An impulse is developed that allows the logs to unload at a reduced angle.

22. Convert Harm Into Benefit

a.Utilize harmful factors — especially environmental — to obtain a positive
effect.
b.Remove one harmful factor by combining it with another harmful factor.
c. Increase the degree of harmful action to such an extent that it ceases to be harmful.

23. Feedback

a.Introduce feedback.
b.If feedback already exists, change it.

24. Mediator

a.Use an intermediary object to transfer or carry out an action.
b.Temporarily connect the original object to one that is easily removed.

25. Self-service

a.An object must service itself and carry-out supplementary and repair operations.
b.Make use of waste material and energy.

26. Copying

a.A simplified and inexpensive copy should be used in place of a fragile original or an object that is inconvenient to operate.
b.If a visible optical copy is used, replace it with an infrared or ultraviolet copies.
c. Replace an object (or system of objects) with their optical image. The image can
then be reduced or enlarged.

27. Dispose

a.Replace an expensive object with a cheap one, compromising other properties (i.e.,
longevity).

28. Replacement of Mechanical System

a.Replace a mechanical system with an
optical, acoustical, thermal or olfactory system.
b.Use an electric, magnetic or electromagnetic field to interact with an object.
c. Replace fields that are:
1. Stationary with mobile.
2. Fixed with changing in time.
3. Random with structured.
d.Use fields in conjunction with ferromagnetic particles.

29. Pneumatic or Hydraulic Constructions

a.Replace solid parts of an object with a gas or liquid. These parts can now
use air or water for inflation, or use pneumatic or hydrostatic cushions.

30. Flexible Membranes or Thin Films

a.Replace customary constructions with flexible membranes or thin film.
b.Isolate an object from its outside environment with flexible membranes
or thin films.

31. Porous Material

a.Make an object porous, or use supplementary porous elements (inserts, covers, etc.).
b.If an object is already porous, fill pores in advance with some substance.

32. Changing the Color

a.Change the color of an object or its environment.
b.Change the degree of translucency of an
object or its environment.
c. Use color additives to observe an object or process which is difficult to see.
d.If such additives are already used, employ luminescent traces or trace atoms.

33. Homogeneity

a.Objects interacting with the main object should be made out of the same material
(or material with similar properties) as the main object.

34. Rejecting and Regenerating Parts

a.After completing its function, or becoming useless, an element of an
object is rejected (discarded, dissolved, evaporated, etc.) or modified during its
work process.
b.Used-up parts of an object should be restored during its work.

35. Transformation of Properties

a.Change the physical state of the system.
b.Change the concentration or density.
c. Change the degree of flexibility.
d.Change the temperature or volume.

36. Phase Transition

a.Using the phenomena of phase change (i.e., a change in volume, the liberation or
absorption of heat, etc.).

37. Thermal Expansion

a.Use expansion or contraction of material by
changing its temperature.
b.Use various materials with different coefficients of thermal expansion.

38. Accelerated Oxidation

a.Make transition from one level of oxidation to the next higher level:
1. Ambient air to oxygenated.
2. Oxygenated to oxygen.
3. Oxygen to ionized oxygen.
4. Ionized oxygen to ozoned oxygen.
5. Ozoned oxygen to ozone.
6. Ozone to singlet oxygen.

39. Inert Environment

a.Replace a normal environment with an inert one.
b.Introduce a neutral substance or additives into an object.
c. Carry out the process in a vacuum.

40. Composite Materials

a.Replace homogeneous materials with composite ones.