DAAT · LEVEL 3 — MASTER SYNTHESIS
Siman שמ"ט
סימן שמ"ט · דִּין אַרְבַּע אַמּוֹת בִּרְשׁוּת הָרַבִּים
Recap & mnemonics for review
📑 Synthesis Outline
- The central axiom of the siman
- The key concepts condensed
- Measuring the 4 amos
- Decision tree
- Overlapping zones
- Mnemonic אַרְבַּע
- Pitfalls to avoid
- Practical cases
- Final summary table
- The practical directives
1. The central axiom
Siman שמ"ט in one sentence.
Carrying beyond 4 amos in reshus harabim is forbidden by the Torah — but within these 4 amos, everyone has a "personal zone" where carrying is permitted. The siman sets the measurement (by one's own amah, diagonal included) and governs the cases where several people's zones overlap.
Carrying beyond 4 amos in reshus harabim is forbidden by the Torah — but within these 4 amos, everyone has a "personal zone" where carrying is permitted. The siman sets the measurement (by one's own amah, diagonal included) and governs the cases where several people's zones overlap.
2. The key concepts condensed
| Concept | Definition | Application |
|---|---|---|
| אַרְבַּע אַמּוֹת | Personal zone in reshus harabim | Carrying permitted within |
| אַמָּה שֶׁלּוֹ | Measured by one's own forearm | Minimum: 4 average amos (6 tefachim) |
| אַלְכְסוֹן | Diagonal of the 4×4 square | ≈ 5⅗ amos |
| תְּחוּם | The object's Shabbos limit | Hand-to-hand relay cannot take it out |
| פָּחוֹת פָּחוֹת | Advancing in small segments | Forbidden circumvention |
3. Measuring the 4 amos
Origin: "שְׁבוּ אִישׁ תַּחְתָּיו" — the measure of the outstretched body: 3 amos + 1 to stretch out hands and feet.
↓
Measurement: by the person's own amah — a tall man has larger amos.
↓
Floor: an amah that is too small is raised to the minimum of 4 average amos (6 tefachim each).
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Diagonal: the 4 amos are reckoned "together with their diagonal" ≈ 5⅗ amos; beyond 4 amos in a straight line: patur aval assur.
4. Decision tree
Q1: Does the carrying stay within my 4 amos (diagonal included)?
↓ YES → permitted; beyond → forbidden
Q2: Is it relaying an object hand to hand, each within his 4 amos?
↓ YES → permitted, without taking the object out of the techum (one opinion forbids it)
Q3: Is one seeking to advance the object "little by little" in segments of less than 4 amos?
↓ YES → forbidden (circumvention)
→ At the slightest doubt about the measurement → consult your Rav.
5. Overlapping zones
| Configuration | Rule |
|---|---|
| Two people, overlapping zones (6 amos apart) | They carry in the common zone — without either encroaching from his own zone into the other's |
| Three people, the middle one absorbed (8 amos between the outer ones) | The middle one is permitted with each of the outer ones; the two outer ones are forbidden with one another |
6. Mnemonic אַרְבַּע
א — אַמָּה שֶׁלּוֹ: the 4 amos are measured by one's own amah — at minimum 4 average amos (6 tefachim).
ר — רִבּוּעַ וְאַלְכְסוֹן: it is a square; with its diagonal ≈ 5⅗ amos.
ב — בְּלִי יְצִיאָה מִן הַתְּחוּם: one may relay hand to hand, each within his 4 amos, without taking the object out of the techum.
ע — עֲרָמָה אֲסוּרָה: forbidden to advance "little by little" in segments of less than 4 amos.
7. Pitfalls to avoid
Pitfall 1: Thinking the 4 amos form a line. It is a square; one may carry diagonally (≈ 5⅗ amos).
Pitfall 2: Advancing an object in small segments of less than 4 amos to cover a great distance — this is a forbidden circumvention, even at twilight, even in a karmelis.
Pitfall 3: Relaying an object hand to hand until it leaves its techum — forbidden.
Pitfall 4: In a three-person configuration, thinking that the two outer people can pass an object between them — they are forbidden with one another.
8. Practical cases
| Situation | Analysis | Conduct |
|---|---|---|
| Moving an object within a small radius in the street | Within one's 4 amos | Permitted |
| Passing an object to a close neighbor, each staying in place | Hand-to-hand relay | Permitted (one opinion forbids it) — without leaving the techum |
| Advancing an object "little by little" over a long distance | Circumvention | Forbidden |
| Two people sitting close | Overlapping zones | Shared common zone |
9. Final summary table
| Element | Detail |
|---|---|
| Topic of the siman | The 4 amos — personal carrying zone in reshus harabim |
| Number of seifim | 5 |
| Mishnah Berurah | 19 entries |
| Talmudic source | עירובין מח ע"א ; שבת צו ע"ב — "שבו איש תחתיו" |
| Golden rule | A square of 4 amos, diagonal included; no circumvention by small jumps |
| Practical ruling | Measure carefully; consult your Rav for borderline cases |
10. The practical directives of Siman שמ"ט
For daily conduct
- In reshus harabim, carry only within one's 4 amos (square, diagonal included).
- The measurement is done by one's own amah, minimum 4 average amos.
- Hand-to-hand relay permitted, each in place — without taking the object out of the techum.
- Never advance an object "little by little" to cross the limit.
- In doubt about the measurement — consult your Rav.
- In-depth pilpul — Level 2; Chabad shitah — Level 4.
📚 Study path recap
You have studied Siman שמ"ט across 3 levels:
You have studied Siman שמ"ט across 3 levels:
- 🌱 Level 1 — Base: the 5 seifim, translation, halachic concepts
- ⚡ Level 2 — Lamdan: Talmudic sources, the Rishonim's שיטות, מחלוקות, נפקא מינות
- ✨ Level 3 — Synthesis: axiom, mnemonic, decision tree, practical directives