Method guide · Kaizen and continuous improvement
Kaizen: meaning, principles, kaizen events and how an idea gets closed
Short answer
Kaizen is Japanese for change for the better. In a plant it means continuous improvement made in small steps, every day, by the operators, supervisors and engineers who own the work. Each change is tried on the line, checked against a number, and kept as the new standard only if it worked, so the next improvement starts from a higher base.
Kaizen is the habit of improving the work a little at a time, with everyone taking part. A problem is spotted on the floor, an idea is raised, the team tests a fix with plan, do, check, act, and a fix that works becomes the standard way of working. Most kaizen is small and daily. A kaizen event is a short, focused burst of the same method on one area, usually three to five days.
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What does kaizen mean?
The word joins two Japanese characters: kai, to change, and zen, good. Read together they mean a change for the better, and in everyday Japanese the word is not special; it is used for any improvement. Lean manufacturing gave it a narrower sense: steady improvement of a process by the people who run it, at low cost, with no end date.
On a shop floor you will hear kaizen used three ways. It is a mindset, the belief that every process can be made better and that the operator knows where. It is a daily practice, the small fixes a team makes and records each week. And it is shorthand for a kaizen event, a few days when a team stops normal work to improve one area. The three are connected, and confusing them is the root of most failed programmes, so this guide keeps them apart.
Kaizen is not a cost-cutting drive, a suggestion box, or a one-week project that is finished on Friday. A plant can run a dozen kaizen events a year and still not have kaizen, if nothing changes between the events. For a list of real improvement ideas sorted by department, see 120 kaizen ideas.
Where kaizen came from: Toyota and Masaaki Imai
Kaizen grew up inside the Toyota Production System in the decades after the Second World War. Taiichi Ohno's book Toyota Production System: Beyond Large-Scale Production (English edition, Productivity Press, 1988) treats standard work and its constant revision as the base the rest of the system stands on: a standard is written so that it can be improved, and an operator who finds a better way is expected to change it. Toyota's suggestion system and its small-group activities gave every team a route to do that.
The word reached Western managers through Masaaki Imai. His book Kaizen: The Key to Japan's Competitive Success (McGraw-Hill, 1986) argued that Japanese plants won by improving process a little at a time, with everybody involved, rather than by large investments alone. His second book, Gemba Kaizen (McGraw-Hill, 1997), moved the idea to the floor: go to the gemba, keep standards, practise 5S, remove waste. Both are still the clearest statement of what kaizen was meant to be.
The kaizen event came later, as Western consultants packaged the method into a few intensive days that could show results quickly. That format is useful, but it is a container for kaizen, not the thing itself. Types of kaizen follows the method from daily improvement to radical change.
The six principles of kaizen
Lists of kaizen principles run from five to ten items, and none is official. These six cover what the longer lists say, in the words a supervisor can use at a huddle. They match the free kaizen principles poster.
- Go to the gemba. Look at the work where it happens, with the people doing it, before you decide what is wrong. A problem described in a meeting room is usually a different problem from the one on the line.
- Facts, not opinions. Count or time the thing before you change it and again after. A tally sheet for one shift beats an hour of debate.
- Fix the process, not the person. When something goes wrong, ask what in the method, the tool or the layout allowed it. Blame stops people raising problems, and kaizen runs on problems being raised.
- Small steps, now. A simple change tried today teaches more than a perfect plan next quarter. Keep each change small enough to undo if it does not work.
- Standardize, then improve. Without a written standard there is nothing to improve on and no way to tell whether a change helped. Every change that works is written into the standard.
- Everyone takes part. The operator on the line sees waste that no engineer will, and the supervisor's job includes answering every idea. Kaizen done only by a CI team is a project office, not kaizen.
The five elements of kaizen covers the structures, such as quality circles and a suggestion system, that keep the principles running.
How kaizen works: PDCA and SDCA
Every kaizen, from a five-minute fix to a five-day event, runs on the same loop: plan, do, check, act. Plan the change and say what number should move. Do it on a small scale, one machine or one shift. Check the number against what you predicted. Act: keep the change and write it into the standard, or drop it and try the next idea. The PDSA and PDCA guide explains the cycle and where it came from.
Imai pairs PDCA with a second loop, SDCA: standardize, do, check, act. SDCA holds the current standard steady; PDCA raises it. A team that only runs PDCA keeps improving a process that drifts back the moment attention moves on. A team that only runs SDCA keeps a process stable but never better. In practice the daily huddle runs SDCA (are we working to the standard, and if not, why), and the ideas that come out of it start a PDCA.
The loop every kaizen runs
- 1
Plan
The change and the number it should move - 2
Do
Try it on one shift or one machine - 3
Check
Count again against the prediction - 4
Act
Write it into the standard, or drop it
Back to Plan, from the new standard
| Loop | Job | Who runs it | Where you see it |
|---|---|---|---|
| SDCA: standardize, do, check, act | Hold the current best way and catch drift | Operators and the supervisor, every shift | Standard work at the station, the shift huddle, layered audits |
| PDCA: plan, do, check, act | Raise the standard with a tested change | The person or team with the idea, coached by the supervisor | Quick kaizen sheets, A3s, kaizen events |
The free [PDCA template](/templates/pdca-template) puts one cycle on one page, and the [quick kaizen template](/templates/quick-kaizen-template) is the shortest form of it: before, after, cause, countermeasure, result, and whether the standard changed.
Kaizen vs kaizen event vs kaikaku
The same method comes in different sizes. The size is chosen by the problem: how many people it touches, how much it costs to try, and how long it takes to prove.
| Kind | Who | How long | Typical tools |
|---|---|---|---|
| Daily kaizen (point or quick kaizen) | One operator or a pair, at their own station | Minutes to a few days | Quick kaizen sheet, before and after photo |
| Kaizen teian (suggestion system) | Anyone, through an idea card, board or app | Answered in days, done in days to weeks | Idea form, suggestion board |
| Kaizen event (kaizen blitz, rapid improvement event, kaizen workshop) | A small cross-functional team taken off normal work | Usually 3 to 5 days on the floor, with preparation before and about 30 days of follow-up | Charter, value stream map, standard work, 5S, line balancing |
| Project kaizen | A leader and a part-time team | Weeks to months | A3, DMAIC, PDCA with a project plan |
| Kaikaku (radical change) | Plant leadership | A planned redesign over months | New layout, new line, new process |
Kaikaku means reform, and it is the opposite end of the scale: a large step change decided from the top. It is not kaizen, but plants that have done kaizen for years are the ones that make kaikaku stick, because their people already work to standards and change them.
What a kaizen event is, and is not
A kaizen event is a planned, time-boxed push on one problem in one area. A typical event has a charter agreed a few weeks before (problem, scope, target, team), a first day of training and studying the current state on the floor, two or three days of trying changes, and a last day of writing the new standard and reporting out. The follow-up list after the event matters as much as the week itself: actions not finished in the week get an owner and a date, and the area is checked at 30 days. Kaizen events: planning and execution covers each day.
Use an event when the fix needs several functions in the room at once (production, maintenance, quality, engineering) and a layout or a standard has to change across a whole area. Do not use one for a problem a single operator could fix this afternoon. The kaizen event charter, preparation checklist and facilitator kit cover the event from scoping to report-out.
Flow kaizen and process kaizen
Mike Rother and John Shook's Learning to See (Lean Enterprise Institute, 1999) splits kaizen by level. Flow kaizen improves the whole value stream, the movement of material and information between processes, and is a management job. Process kaizen removes waste inside one process and belongs to the team that runs it. A plant needs both: process kaizen on its own polishes stations that may not be the constraint, and flow kaizen on its own redraws maps that nobody on the line has helped to change.
How a kaizen idea moves from tag to closed
Most kaizen programmes do not fail for lack of ideas. They fail in the middle: the idea is raised, then nobody answers it, or it is done once and never written into the standard. A clear path from the first tag to a closed standard is what keeps people raising the next one.
One idea, from the tag to a closed standard
- 1Operator
Spot it
- 2Operator
Raise it
- 3Supervisor
Answer it
- 4Decision
Small, safe and inside the team's own area?
- Yes:
- do it this shift, or on a quick kaizen sheet
- No:
- a kaizen event, an A3 or a DMAIC project
- 5Owner
Plan, do, check, act
- 6Supervisor
Make it the standard
- 7Team
Close it and share it
- 1
Spot it
An operator notices waste, a near miss or a recurring nuisance during the shift: a long walk, a part that fights the fixture, a check done twice.
- 2
Raise it
The operator writes one idea per card or tag: what happens now, where, and what they suggest. A photo helps. The card goes on the team's suggestion board, or the tag is raised on a phone from a QR code at the station.
- 3
Answer it
The supervisor reviews new ideas at the next huddle and gives every one an answer: approved, approved with changes, parked with a reason, or not this time with a reason. Set a response time, for example two working days, and track it. An unanswered idea is the fastest way to stop the next one.
- 4
Choose the route
Size decides the route. Safe, cheap and inside the team's own area: just do it this shift. A few days and one owner: a quick kaizen sheet. Several functions or a layout change: a kaizen event. Unknown root cause or large cost: an A3 or a DMAIC project.
- 5
Run plan, do, check, act
Measure before. Try the change on one shift or one machine. Measure after, against the number you predicted. If it missed, adjust and try again, or drop it and say why.
- 6
Make it the standard
Update the standard work or SOP, mark the new location or setting on the floor, and teach it to every shift, often with a one-point lesson. Without this step the old way comes back within weeks.
- 7
Close it and share it
Record the before and after and the result. Close the idea only when the person who raised it agrees the problem has gone. Thank them in front of the team, and send the change to similar lines (yokoten).
A kaizen board or suggestion board at the huddle makes the path visible: columns for submitted, answered, in progress and done, a card per idea and an owner per card. The idea suggestion form has an idea log that counts the days to answer, and the kaizen action tracker holds the actions that come out of events. Kaizen teian covers how a suggestion system answers and rewards ideas, and yokoten how a fix travels to other lines.
A kaizen example: the carton walk in a packing cell
This example is illustrative. A packing cell runs two shifts and packs 480 cases a shift. Flat cartons are kept in a rack 15 metres away, in bundles of 20. The packer raises an idea: I walk to the carton rack all shift, can the cartons come to me?
Plan: count before changing anything
The supervisor approves it at the huddle as a quick kaizen. The packer and the team leader tally one shift: 480 cases need 24 bundles, so 24 trips to the rack. They time five trips; walking there, picking up a bundle and walking back takes about 90 seconds. The prediction: a small flow rack at the cell, refilled by the water spider on his existing route, should cut each fetch to a reach of about 5 seconds.
Do and check: trial, then count again
| Step | Calculation | Result |
|---|---|---|
| Bundles needed per shift | 480 cases / 20 cartons per bundle | 24 bundles |
| Before: time fetching cartons | 24 trips x 90 s | 2,160 s, which is 36 minutes |
| After: time reaching for cartons | 24 reaches x 5 s | 120 s, which is 2 minutes |
| Time returned to the cell | 36 minutes minus 2 minutes | 34 minutes a shift |
| Per day, two shifts | 34 minutes x 2 | 68 minutes a day |
Check it the other way: each fetch saves 90 minus 5 = 85 seconds, and 85 s x 24 = 2,040 s, which is 34 minutes a shift. Over a five-day week of two shifts that is 34 x 10 = 340 minutes, or 5 hours 40 minutes. The [kaizen savings calculator](/tools/kaizen-savings-calculator) turns time saved into a yearly figure with your own labour rate.
The trial runs for two shifts with a borrowed rack. The tally after matches the prediction, and the water spider confirms the refill fits into the route he already runs, so the walk has not just moved to someone else.
Act: make it the standard and share it
The rack position is marked on the floor, the rack gets a minimum line and a refill card, the packing standard work is updated, and the night shift gets a one-point lesson. The idea is closed with the packer's agreement and both tally sheets attached. The same change goes to the two other packing cells the next week. The packer's next idea, about label reprints, is on the board by Friday: that is the real result.
Kaizen vs lean vs Six Sigma
Kaizen, lean and Six Sigma overlap, and most plants use all three. The difference is mostly in scale, who does the work, and how much data the problem needs.
| Kaizen | Lean | Six Sigma | |
|---|---|---|---|
| What it is | A habit of small, continuous improvement by everyone | A whole operating system built on flow, pull and waste removal | A project method for cutting variation and defects |
| Typical size | Small changes, many of them | From one cell to the whole value stream | One project with a defined problem and a financial target |
| Who does it | Operators and supervisors, coached by leaders | Everyone, led by management | Trained Green Belts and Black Belts with a project team |
| Main tools | PDCA, quick kaizen sheets, kaizen events, 5S | Value stream mapping, standard work, kanban, takt time | DMAIC, statistics, capability studies, designed experiments |
| Best for | Waste and nuisance problems the team can see | Long lead times, stock and poor flow | Defects with an unknown cause buried in variation |
Kaizen sits inside lean as the improvement engine, and a Six Sigma project is one route an idea can take when the cause is hidden. The [PDCA, DMAIC and A3 poster](/posters/pdca-dmaic-a3-poster) shows when to pick which cycle.
How to start kaizen in one area
Start small and in one place, so the first results are visible and the routine is proven before it spreads. A workable first month in one cell or line:
- Week 1: write or refresh the standard work for the area, so there is something to improve. Put up a suggestion board at the huddle point.
- Week 1: agree the answer rule with the supervisor: every idea answered at the next huddle, with a reason if the answer is no.
- Weeks 2 to 4: ask each person for one small problem a week in a 10 to 15 minute daily slot at the board. Use the daily kaizen routine to run it and count the ideas raised, answered and closed.
- Week 4: review the closed ideas with the team, put the before and after photos on the board, and pick one larger problem for a quick kaizen or an event.
- After that: move to the next area only once the first one runs without the CI lead in the room. The model area guide sets out the 90-day version.
The benefits of kaizen covers what a sustained programme delivers, and continuous improvement for beginners sets kaizen among the other improvement methods.
Common kaizen mistakes
- Treating kaizen as the event. Plants that only run kaizen events get a burst of change twice a year and slide back in between. The daily loop is the kaizen; the event is a booster.
- Leaving ideas unanswered. A suggestion box opened once a month teaches people that ideas go nowhere. Answer every one, quickly, even when the answer is no.
- Improving without a standard. If the current method is not written down, nobody can tell whether a change helped, and the improvement is lost when the person who made it moves shift.
- Skipping the check. A change that felt better is not a result. Count before and after, even with a tally sheet.
- Measuring kaizen only in money. Savings matter, but a programme judged only on dollars stops the small safety and ergonomic fixes that build the habit. Count ideas raised, answered and closed as well.
- Running kaizen through the CI team only. If the CI engineer writes every improvement, the operators are spectators. The CI lead's job is to coach the supervisor who coaches the team.
Kaizen software
Run kaizen in LeanSuite
Each Kaizen runs from charter to closure with A3, DMAIC, PDCA, 8D or your own method, and a recurring issue becomes a Kaizen in one click.
Go deeper
This page is the short version. These guides cover each part in full.
- Types of Kaizen: From Daily Improvements to Radical TransformationEach type of kaizen in more depth, from daily kaizen and teian to kaikaku and kakushin, and how to choose.
- Kaizen Events: Planning and Execution GuideTeam make-up, the week of preparation and the five-day structure of a kaizen event, day by day.
- The Five Elements of Kaizen in ManufacturingThe structures that keep kaizen running: teamwork, discipline, morale, quality circles and suggestions.
- Kaizen Teian: Individual Improvement SuggestionsHow a suggestion system takes, answers and rewards individual ideas.
- PDCA Cycle: The Foundation of Continuous ImprovementThe four phases of PDCA in manufacturing and how the cycle drives each kaizen.
- Yokoten: Horizontal Deployment of Kaizen Best PracticesHow a kaizen that worked on one line is copied, and adapted, across lines and sites.
All our articles on this subject are in the kaizen and continuous improvement topic.
Free templates and tools
- Suggestion boardIdeas move from submitted to review, approved, in progress and done, with an owner per card, as a Lean Studio board.
- Kaizen action trackerEvery improvement action with its owner, due date and status on one board reviewed weekly, in Lean Studio.
- Quick kaizen templateOne page for a small improvement: before and after, the cause, the countermeasure, the results and whether the standard changed.
- Idea suggestion formA one-page idea form with the supervisor's answer and points, and an idea log that tracks days to answer.
- Kaizen event charter templateProblem, goal, scope in and out, boundaries, metrics from baseline to target, team and roles, and sign-off before day one.
- PDCA templateOne improvement cycle on one page: plan, do, check against the goal, then standardize or adjust. PDF and Excel.
- Daily kaizen routine boardA team's 10 to 15 minute daily routine at the board: one problem from each person, small fixes with one owner, counted every week.
- Kaizen savings calculatorYearly savings, payback in months and first-year ROI of an improvement, from time saved, scrap avoided and its costs.
Doing this in LeanSuite
Idea Management
A digital suggestion system: operators submit ideas from a phone or shared tablet, reviewers answer every one, and the best become kaizen projects with the link to the original idea kept.
See Idea ManagementDaily Issue Management
Gives frontline teams one place to flag, track and resolve issues in real time, so the same fires stop coming back every week.
See Daily Issue ManagementKaizen & Projects
Manage every improvement project in one visual hub, from a small kaizen event to a full DMAIC project, and track each one through to results.
See Kaizen & Projects
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Questions about kaizen
It joins two Japanese characters, kai, to change, and zen, good, so it means change for the better. In lean manufacturing it means continuous improvement: small, frequent changes to a process, made by the people who do the work, each one tested and then kept as the new standard.
Kaizen is best defined as continuous, incremental improvement that involves everyone, from operators to managers. It is a daily habit rather than a project: spot a problem, try a small fix with plan, do, check, act, and write the fix into the standard if it works.
The core principle is that many small improvements, made all the time by the people closest to the work, add up to more than occasional big changes. It works through two loops: SDCA holds the current standard steady, and PDCA tests a change and raises the standard when the change works.
Pick one problem you can see at your own workstation. Count or time it for a shift. Try one small change on one shift. Count again and compare with what you expected. If it worked, update the standard work and teach the other shifts; if not, try the next idea. Record the before and after on a one-page quick kaizen sheet.
Kaizen is the ongoing habit of small improvements made every day by everyone. A kaizen event, also called a kaizen blitz or rapid improvement event, is a planned burst of the same method: a small cross-functional team spends usually three to five days improving one area, then follows up for about a month.
Most kaizen events run three to five days on the floor. Around that sit a few weeks of preparation, to agree the charter, team and baseline data, and about 30 days of follow-up to finish open actions and check the new standard is holding.
Kaizen is a habit of many small improvements made by everyone, using simple tools such as PDCA and before and after counts. Six Sigma is a project method run by trained Belts, using DMAIC and statistics to cut variation and defects with a hidden cause. Many plants use kaizen for daily problems and Six Sigma for the few that need data analysis.
At Toyota, kaizen is part of the daily job. Standard work is written so that it can be improved, operators and team leaders are expected to raise and test improvements, and a change that works becomes the new standard. Taiichi Ohno described standard work and its revision as the base of the Toyota Production System.
There is no official list of ten rules; the versions shared on posters vary and have no single source. They usually say, in different words: drop fixed ideas, think about how it can be done instead of why it cannot, start now even if the fix is only half right, correct mistakes at once, use ideas before money, ask why until you reach the cause, and ask many people rather than one expert.
There is no standard twelve-step kaizen method. Every kaizen follows plan, do, check, act. A practical path for one idea has seven steps: spot it, raise it, answer it, choose the route, run plan, do, check, act, make it the standard, and close and share it. Kaizen events add preparation before and follow-up after.
A packer who walks 24 times a shift to a carton rack 15 metres away suggests bringing the cartons to the cell. A flow rack refilled by the water spider cuts each fetch from about 90 seconds to 5, which returns 34 minutes a shift. The rack position and refill are written into the standard and copied to the other packing cells.
Related guides and tools
- Kaizen ideas: 120 improvement examples by department, each with the problem and the effort
- Kaizen poster: the six principles and four steps to a first improvement, free to print
- Kaizen savings calculator: yearly savings, payback and first-year ROI of an improvement
- PDSA and PDCA cycle: the loop every kaizen runs on, with a worked shop-floor example
- Masaaki Imai's Kaizen (1986): the book that brought the word to Western managers
- Employee suggestion program software: from idea to kaizen
- Free e-book, readable online: how to run a kaizen campaign on one urgent problem, step by step
- Free e-book, readable online: getting operators to report problems and ideas with a suggestion program
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