The example checks four small object cards against a declared key. J1 is one pencil, J2 two pencils, J3 three pencils, and J4 three separate paper sheets. Choose a card, enter the quantity, counter, written count, and kana reading, then check each dimension. The completed J1 model shows what an aligned answer looks like without presenting it as actual learner work.
Define the counted unit
Use individual pencils and separate loose sheets. A bundle, pair, or bound notebook would be another task requiring another reviewed key. For this bank, pencils use 本, the long-thin-object counter, while sheets use 枚, the flat-thin-object counter. The UT Austin JOSHU reference lists those categories. Keep the written description with each card so the task does not rely only on a drawing. The quantities are authored fixtures, not counts inferred from a learner's photograph or a live camera.
The key is J1 一本 / いっぽん, J2 二本 / にほん, J3 三本 / さんぼん, and J4 三枚 / さんまい. The Japan Foundation's Marugoto appendix supplies the selected readings. This practice uses kana as its explicit answer route. If you offer romanization in class, agree the accepted forms before the turn rather than penalizing an unannounced convention. Do not generalize the four answers into a rule that attaching hon unchanged produces the reading for every number.
Start with a useful contrast
Begin with J1 and its authored completed response. Then switch to J3. Count three separate pencils, choose 本, write 三本, and enter さんほん as the first attempted reading. The quantity, counter, and written-count checks match; the reading check asks for さんぼん. The learner has a specific revision to make. Avoid replacing the whole answer with a single wrong badge that hides which of the earlier decisions were already consistent with the card.
Select J4, then enter 3 / 本 / 三本 / さんぼん again as a deliberately authored mismatch. Quantity agrees with the card, but the stated sheets need 枚 and 三枚 / さんまい. The reading さんぼん agrees with the submitted written form 三本, even though that form does not answer J4. Show both relationships: consistency within the response and consistency with the target card. A correct reading of the wrong count-counter expression is useful evidence for deciding what to reteach.
Finish with an explained choice
Ask partners what stayed the same between J3 and J4. Both quantities are three; the object category changes. “I counted separate sheets, so I chose the supplied flat-thin category” is more informative than memorizing that three means 三本. Use the stable card IDs when shuffling the order. The key follows J3 or J4, not a button's position or a picture's color. Have the teacher review the language and materials before adding new objects to this bounded bank.
Missing fields remain incomplete; the page does not substitute zero or a default counter for an unanswered field. Card changes and edits clear old feedback, while Reset returns to unanswered J1. A text comparison checks the written response only: it does not listen to pronunciation, assess proficiency, or store learner records. Keep oral observations separate. Close by asking the learner to name the unit, justify the category, and read the reviewed written count with the teacher rather than relying on an undifferentiated score.
Make your own working example
Build a Japanese counter practice page with four stable card buttons: J1 one individual pencil, J2 two pencils, J3 three pencils, J4 three separate loose sheets. Key J1 1 / 本 / 一本 / いっぽん; J2 2 / 本 / 二本 / にほん; J3 3 / 本 / 三本 / さんぼん; J4 3 / 枚 / 三枚 / さんまい. Keep object descriptions visible and preserve Japanese Unicode. Mark Japanese key passages and Japanese response fields with lang="ja", while keeping English labels in English.
Use labeled quantity, counter, written-count, and kana-reading fields. Start with a completed authored J1 example. Check reports quantity, counter, written count, and target reading separately, plus whether the reading agrees with the submitted known written count. J3 with さんほん needs only reading revision. J4 with 3/本/三本/さんぼん has correct quantity and an internally consistent submitted reading but the wrong counter and target expression.
Require all four fields before checking; blanks stay incomplete. Card changes clear answers and feedback. Input edits clear old feedback. Reset restores J1 unanswered. This is a four-card written comparison, not object recognition, a general counter engine, or pronunciation scoring.
Use one self-contained HTML file with no remote dependency. Keep the initial sample, output, and labeled controls near the top. Use at least 16px text, strong contrast, visible focus, and a stacked layout at 360px without horizontal overflow. Use explicit type=button click handlers and explicit DOM selectors; do not depend on native form submission. Clear stale feedback when task inputs change. Render entered text safely. Keep practice data local to the current page; do not imply saving, sending, or production integration. Return only the finished HTML.
Prepare the next class copy
Before reusing J4, clarify the static key explanation that separate sheets use 枚, then have the teacher review their choice of counter and kana reading. In NOS, eligible static instructions can be revised in visual editing mode without asking AI to regenerate the HTML. Keep the teacher's source packet and actual learner work separately; use the reading copy to clarify the next activity.