Katori Mode: Deducting the Bowl (and the Moisture) Before the Weight Is Recorded

The katori is on every scale in the mandi. The deduction should be in the record too.

Every trader’s counter has one: a steel bowl or a crate whose weight is taken off the pan and never written down. Then comes the second cut — a percentage for wet grain, agreed with a nod. People search for it as container weight deduction scale humidity. In the mandi it has a shorter name: katori. The “humidity” that matters is the moisture inside the grain, not the air. Here is what the law says about both deductions, what a moisture cut is honestly worth in rupees, and how a Katori-mode scale from Hindustan Scale Company puts each one on the slip, labelled, with the name of the person who switched it on.

The katori is a tare, and the law wants it in the record

Deducting the bowl feels like a courtesy. In law it is a regulated function with a name: tare.

The international model regulation for trade scales, OIML R 76-1 (2006), defines a preset tare as a stored container weight subtracted from the gross — “keyed in, recalled from a data storage device, or inserted via an interface”. A bowl weight saved in the scale or sent from an app is exactly that. And when it is used, the display marks the reading NET, and if the net is printed, the tare is printed beside it, marked T or PT, so nobody can mistake it for goods.

India wrote those words into its own rulebook. The Legal Metrology (General) Rules 2011, Seventh Schedule, require that net and tare values “at least be identified by the corresponding symbol N and T”, and that when a calculated net is printed, “at least the preset tare value is printed as well”, marked PT. The US rulebook, NIST Handbook 44 (2026 edition), requires the tare weight on point-of-sale records for equipment made since 01/01/2025; the EU directive wants printed results “suitably identified and unambiguous”. Four regulators, one rule: the container deduction goes into the record, labelled.

And it may not be silent. On scales that sell to the public — the class up to 100 kg at most mandi and retail counters — the Indian rules say the customer must be able to see that a tare is in use, no automatic tare device is allowed, and the tare can be cancelled only when the pan is empty. Switched on by a person, for a named container, visibly.

Is a container weight deduction scale humidity factor legal in India?

Yes for the container. Only with a label for the moisture. And the two must never share a line.

A tare is a mass — the bowl weighs 2.4 kg and always will. A moisture cut is a percentage opinion about the goods. OIML R 76-1 counts only gross, net and tare as weighing results; anything else a scale shows must be “clearly identified” as something other than the weight, or it may be shown only for a moment and never printed. India’s rules add that an app may not feed a scale “data that are not clearly defined and could be mistaken for a weighing result”.

The government’s own grain purchases show how it is meant to work. The Department of Food and Public Distribution’s Handbook of Quality Control (27/06/2024) buys wheat above 12 % moisture with a “value cut” — 1 % of MSP up to 13 %, 2 % up to 14 %, rejection beyond — and its Uniform Specification letter of 15/02/2024 says the excess moisture “will be discounted at full value”. The weighed quantity is never touched. The price is.

So the rule is simple. Gross minus katori equals NET, marked as such — that is the legal weight. The moisture factor is a separate line underneath, labelled as a percentage, logged, and applied after the weighment. It changes what is paid, not what was weighed.

What a moisture cut is honestly worth

Grain does lose weight as it dries, and the amount is arithmetic, not negotiation. The International Rice Research Institute publishes the standard drying formula — final weight = initial weight × (100 − initial moisture) ÷ (100 − final moisture) — and the North Dakota State and Purdue extension services build their shrink tables on it.

Apply it to paddy against the government ceiling of 17 % moisture, uniform across India, as the Food and Public Distribution ministry confirmed in the Lok Sabha on 17/12/2025. Rupee values are arithmetic on the MSP.

Paddy arrives at	Weight once dried to 17 %, per quintal	Loss	Worth at MSP ₹2,441 a quintal
19 %	97.6 kg	2.4 kg	about ₹59
20 %	96.4 kg	3.6 kg	about ₹88
22 %	94.0 kg	6.0 kg	about ₹147

The MSP is the Cabinet’s figure of 13/05/2026: ₹2,441 a quintal for common paddy in 2026-27, ₹2,461 for Grade A. Wheat is ₹2,585, so one point of the government’s wheat value cut is ₹25.85 a quintal.

Now compare what farmers say is being taken. On 03/10/2025 and 11/10/2025 The Tribune reported farmers in Karnal district receiving “kachi parchi” raw slips ₹100 to ₹700 a quintal below MSP, citing moisture, while the official record showed full MSP paid. On 14/09/2026 a former ICAR scientist wrote to the Haryana government that traders reportedly cut about ₹300 a quintal once moisture passes 17 % — against a true drying loss at 19 % of roughly 2 kg, about ₹50. The gap between ₹59 and ₹300 is not moisture. It is price, and a price decision belongs on the slip, labelled as one.

One more reason to write the percentage down: the number itself is soft. Under OIML R 59 (2016), the international standard for grain moisture meters, a meter in service on paddy at 17 % may read 0.85 of a point high or low and still pass. A figure with nearly a point of built-in doubt cannot be applied from memory. R 59 lists what a moisture record must carry — date, grain type, sample ID, result, meter and calibration ID — and that is the template.

Why the record, not the weighment, is what matters now

Three things now bear down on the katori.

The law was already there. The Legal Metrology Act 2009 voids any “custom, usage, practice or method” that lets a buyer receive more than the quantity contracted for (section 12). A buyer who fraudulently receives more than was paid for faces a fine up to ₹10,000 and, on a second offence, up to a year in prison (section 30). Every trade scale must be verified and stamped before use (section 24). A deduction that exists only in someone’s head is exactly what section 12 was written against.

Procurement now demands the slip. West Bengal’s paddy policy for KMS 2025-26 requires paddy to be “weighed and checked in presence of the farmer” on scale-linked purchase devices, with “an acknowledgement slip generated after confirmation by the farmer” printed on the spot.

The reading leaves the scale anyway. A connected scale sends each weighment to a phone, a printer, a dashboard or an ERP (see IoT connected weighing scales). If the deduction is not in that stream, the ERP holds a weight the farmer never agreed to.

How Katori mode works on an HSCo scale

HSCo builds Katori mode into its Bluetooth platform and table-top scales and into the Android app that talks to them. It does what the rulebook describes, and no more.

1. The container is chosen, not guessed. The operator selects a named container — this bowl, that crate — and switches its stored weight on. Nothing is applied automatically to whatever lands on the pan.
2. The screen says NET while it is on. Trader and farmer both see it.
3. Three numbers go into the record, not one: gross, container and net.
4. The moisture factor is a separate, deliberate line. The owner or supervisor must enable it; an operator cannot switch it on in passing. It is shown and logged as a labelled percentage after the legal net — never in place of it.
5. Every weighment is saved with its context: gross, container deduction, net, the moisture percentage applied, who enabled it and when. It exports to Excel or the ERP and travels over Bluetooth or Wi-Fi as a full record, not a bare number.
6. The farmer leaves with paper. With the thermal-printer add-on, the slip prints gross, PT, N and the moisture line.

The percentage still has to come from somewhere honest: a calibrated grain meter at the counter, or an HSCo moisture analyser for the sample that settles a dispute. Katori mode records which number was used.

What Katori mode is not

It is not an automatic tare. The standards forbid one on a direct-sales scale, and so does Katori mode: a person picks the container, every time.

It is not a way to hide a cut. It exists to put the cut on the slip. If a deduction cannot survive being printed, it should not be made.

It is not a substitute for stamping. The scale is still verified under the Act; Katori mode changes the paperwork, not the legal weight.

It is not a moisture meter. It records the percentage you decide to apply.

What changes on Monday morning

1. Both deductions are visible. The screen shows NET, the slip shows PT and the moisture line, and the farmer sees both before leaving.
2. The kachi parchi has nothing to say. There is no reason for a second slip when the first one already carries the deduction.
3. Every deduction has a name and a time. A dispute becomes a look-up: which container, which percentage, who enabled it, when.
4. The ERP receives the true numbers. Gross, tare, net and moisture arrive as four fields, not one that was quietly adjusted.

How to start: one counter, thirty days

1. Pick one counter — the one with the most arguments.
2. Weigh every katori, crate and bag you use, and name each one in the scale.
3. Decide who may enable the moisture factor — the owner or a named supervisor — and what evidence they need first.
4. Print a slip for every weighment for thirty days, with PT, N and the moisture line on it.
5. Count disputes raised, slips challenged and minutes spent arguing. Roll out what the numbers justify.

Hindustan Scale Company has made weighing scales in Mumbai since 1955 and builds the scale, the app and the printer link itself. The counter scales are on the table-top scales page.

Frequently asked questions

Is deducting the katori weight legal?

Yes — it is a tare, a regulated function under OIML R 76-1 and India’s Legal Metrology (General) Rules 2011. The rules only ask that it be visible: the display shows NET while it is on, and the printed slip carries the tare or preset tare value marked T or PT beside the net.

Can a scale deduct moisture automatically?

No, and it should not try. A moisture cut is not a weighing result, so a scale or app may show it only as a clearly labelled separate figure, never as the weight. The government’s own procurement applies moisture as a value cut on the price, leaving the weighed quantity untouched, and that is the model to copy.

How much weight does paddy really lose when it dries?

By the standard drying formula, a quintal at 19 % moisture becomes 97.6 kg at 17 %, a loss of 2.4 kg, worth about ₹59 at the 2026-27 MSP of ₹2,441. At 20 % the loss is 3.6 kg and at 22 % it is 6.0 kg. A cut larger than that is a price decision and should be written down as one.

What should a weighing slip show when a container is deducted?

The gross weight, the container weight marked T or PT, and the net marked N — plus the moisture percentage on its own labelled line if one was applied. Adding the scale’s identity, the slip number, the date and time, and who enabled each deduction makes the record defensible later.

Which HSCo scales have Katori mode?

HSCo’s Bluetooth platform and table-top scales, working with the HSCo Android app; the thermal-printer add-on prints the slip and the app exports the records to Excel or an ERP. Tell us the counter and the goods, and we will confirm the right model.

Why does the article say moisture rather than humidity?

Because the deduction is about water inside the grain, measured by a moisture meter or the oven test that India’s procurement handbook defines, not about damp air. “Humidity” is the word people search for; “moisture content” is the one the rules, the meters and the mandi actually use.

Next step

Tell us which counter argues the most, and we will set up a Katori-mode scale, app and printer there for a thirty-day trial.

Hindustan Scale Company (HSCo) · Mumbai · est. 1955 · www.hindustanscale.com · hsc@hindustanscale.com

Sources

1. OIML R 76-1 Edition 2006 (E) — Non-automatic weighing instruments, Part 1 (International Organization of Legal Metrology): tare and preset tare definitions (T.2.7.4, T.2.7.5, T.5.3.1); NET indication (4.6.5); N/T printing symbols (4.6.11); preset tare printed with the net and marked PT (4.7.3); direct-sales restrictions (4.13.3–4.13.4); non-weighing values must be clearly identified or never printed (4.4.4).
2. Legal Metrology (General) Rules, 2011 — Seventh Schedule, Heading A, Specification for Non-Automatic Weighing Instruments (Government of India): tare device (6), preset tare “PT” (7), direct-sale primary indications visible to vendor and customer (13), interface data that could be mistaken for a weighing result.
3. The Legal Metrology Act, 2009 (Act 1 of 2010), sections 12, 24, 25, 30 and 33, with the Jan Vishwas (Amendment of Provisions) Act, 2023.
4. NIST Handbook 44, 2026 edition, Section 2.20 Scales, S.1.8.5 and S.2.3 (USA); Directive 2014/31/EU, Annex I, paragraphs 9, 10, 13 and 14 (EU).
5. Lok Sabha Unstarred Question No. 2765, Moisture content in paddy, answered 17/12/2025 (Ministry of Consumer Affairs, Food and Public Distribution).
6. Department of Food and Public Distribution — Handbook of Quality Control V24.01, 27/06/2024 (Chapters 2, 3, 5, 8, 9 and 11); DFPD letter No. 8-1/2022-S&I of 15/02/2024, Uniform Specifications of Wheat, RMS 2024-25, circulated by FCI headquarters.
7. Press Information Bureau — CCEA releases on MSP for kharif crops 2026-27 (13/05/2026) and rabi crops 2026-27 (01/10/2025); corroborated by Business Standard (13/05/2026) and ANI (01/10/2025).
8. Government of West Bengal, Department of Food and Supplies — Policy and Guidelines for procurement of paddy and CMR during KMS 2025-26, paragraphs 3.17.12 and 7.13–7.19.
9. International Rice Research Institute, Rice Knowledge Bank — Moisture content calculations; Methods in measuring moisture content for drying; Using moisture meters (accessed 15/09/2026).
10. North Dakota State University Extension — K. Hellevang, Get Accurate Moisture Content Measurements, 02/11/2009; Purdue University / North Central Regional Extension publication NCH-61, Calculating Grain Weight Shrinkage in Corn Due to Mechanical Drying; Iowa State University Ag Decision Maker A2-32, Corn Drying and Shrink Comparison (2014).
11. OIML R 59-1 Edition 2016 (E) — Moisture meters for cereal grains and oilseeds, Part 1: clauses 4.3, 4.4.2, 4.5, 5.6, 5.7, 5.14 and 5.18.6.2.
12. The Tribune, Karnal, 03/10/2025 and 11/10/2025; Amar Ujala, Jind, 07/10/2025; Kisan Tak, 14/09/2026; The Times of India, Chandigarh, 15/09/2026 — reports of moisture-named deductions, “kachi parchi” slips and the 17 % procurement limit.
13. Hindustan Scale Company — Katori mode on Bluetooth platform and table-top scales, the HSCo Android app, thermal-printer add-on and moisture analysers (2026).