DAAT · LEVEL 3 — MAGISTERIAL SYNTHESIS
Siman שס״ט
סימן שס״ט · באיזה אופן מקנין העירוב
Recap & mnemonics for review
📑 Synthesis plan
- The central axiom of the siman
- The condensed key concepts
- The ways of acquiring — in the order of the seif
- Decision tree — has the one who pays for his share acquired the eruv?
- The Mechaber and the Alter Rebbe — where their texts differ
- Mnemonic עכב
- Pitfalls to avoid
- Practical cases
- Final synthesis table
- The practical commandments
1. The central axiom
Siman שס״ט in one sentence.
One who gives money for his share in the courtyard eruv acquires it, or does not, according to the way he went about it, among other things: what he said (זכה לי or ערב לי), what he handed over (a coin or an article), the person he handed it to (the baker or a private householder), and what the baker then did (having it acquired for him through another, buying him bread at the market with the coin) — seif א. The coin alone, given to the baker with “acquire for me”, gives him no share: « זכה לי בעירוב שיהא לי חלק עמהם בשביל מעה זו אינו עירוב » (שו״ע או״ח שס״ט:א). The reason: money does not acquire before meshichah, as the Mishnah Berurah writes on the article, « דדוקא מעות אינן קונות עד שימשוך החפץ אבל אם מקנה לו כלי הוי חליפין » (משנה ברורה שס״ט ס״ק ד); when the baker counted him among all without naming him, the reason it gives is first that, by default, he did not mean to give it to him as a gift, and then that money does not acquire (ס״ק ב).
One who gives money for his share in the courtyard eruv acquires it, or does not, according to the way he went about it, among other things: what he said (זכה לי or ערב לי), what he handed over (a coin or an article), the person he handed it to (the baker or a private householder), and what the baker then did (having it acquired for him through another, buying him bread at the market with the coin) — seif א. The coin alone, given to the baker with “acquire for me”, gives him no share: « זכה לי בעירוב שיהא לי חלק עמהם בשביל מעה זו אינו עירוב » (שו״ע או״ח שס״ט:א). The reason: money does not acquire before meshichah, as the Mishnah Berurah writes on the article, « דדוקא מעות אינן קונות עד שימשוך החפץ אבל אם מקנה לו כלי הוי חליפין » (משנה ברורה שס״ט ס״ק ד); when the baker counted him among all without naming him, the reason it gives is first that, by default, he did not mean to give it to him as a gift, and then that money does not acquire (ס״ק ב).
2. The condensed key concepts
| Concept | Definition | In the seif |
|---|---|---|
| זכה לי | “Acquire for me”: he asks the baker to have a share acquired for him in exchange for the coin | With the coin alone, given to the baker, it is not an eruv; among other ways, with an article, or given to a private householder, he has acquired the eruv; see also the rows ע״י אחר and לחם מן השוק (seif א) |
| מעות אינן קונות | Money alone does not acquire; an article does: « דדוקא מעות אינן קונות עד שימשוך החפץ אבל אם מקנה לו כלי הוי חליפין » (משנה ברורה שס״ט ס״ק ד) | For the first case, the Mishnah Berurah makes it the second branch of its reason, after the baker's intention: « והטעם דמסתמא לא כוון ליתן לו במתנת חנם כמו לאחרים אלא בשביל מעות שנתן לו ומעות אינן קונות נמצא שאין לו חלק בעירוב » (משנה ברורה שס״ט ס״ק ב) |
| וזכה גם לזה עמהם | The baker counted him among everyone: « ר״ל בכלל כל בני החצר ולא פרט שמו בהדיא » (משנה ברורה שס״ט ס״ק ב) | With the coin alone and “acquire for me”, this is not enough (seif א); with “make the eruv for me”, or with a private householder, inclusion among everyone suffices according to the Mishnah Berurah (ס״ק ג and ח) |
| ערב לי | “Make the eruv for me”: « הרי עשאו שליח לערב לו באופן שיועיל » (משנה ברורה שס״ט ס״ק ג) | He has acquired the eruv (seif א) |
| כלי | The article handed over as a kinyan: « אבל אם מקנה לו כלי הוי חליפין » (משנה ברורה שס״ט ס״ק ד) | With “acquire for me”, he has acquired the eruv (seif א) |
| ע״י אחר | Acquisition made for him through a third party: « ר״ל שפרט שמו בהדיא ולא בסתמא עם אחרים » (משנה ברורה שס״ט ס״ק ה); the reason, « מטעם דזכין לו לאדם שלא בפניו » (משנה ברורה שס״ט ס״ק ה) | He has acquired the eruv (seif א) — naming him, according to the Mishnah Berurah (ס״ק ה); the boundary is disputed: Pitfall 4; but « ויש מאחרונים שחולקין ע״ז » (משנה ברורה שס״ט ס״ק ו) |
| לחם מן השוק | Bread bought at the market with the coin: « דנעשה בזה כשלוחו וקנה זה את הלחם » (משנה ברורה שס״ט ס״ק ז) | He has acquired the eruv (seif א) |
| בעל הבי׳ | The private householder, as opposed to the baker: « לפי שאין דרך בעה״ב למכור משלו » (משנה ברורה שס״ט ס״ק ח) | A coin and “acquire for me”: he has acquired the eruv (seif א) |
3. The ways of acquiring — in the order of the seif
The coin to the baker, with “acquire for me” → « זכה לי בעירוב שיהא לי חלק עמהם בשביל מעה זו אינו עירוב » (שו״ע או״ח שס״ט:א), and this even if the baker made the eruv for everyone and « וזכה גם לזה עמהם » (שו״ע או״ח שס״ט:א): according to the Mishnah Berurah, he was counted among everyone without being named, and, by default, the baker did not mean to give it to him as a gift (ס״ק ב).
↓
“Make the eruv for me” → « אבל אם אמר לו ערב לי קנה עירוב » (שו״ע או״ח שס״ט:א): he made the baker his agent (Mishnah Berurah, ס״ק ג).
↓
“Acquire for me”, with an article → « ואפילו אם אמר זכה לי אם נתן לו כלי בתור׳ קנין שיקנה לו בו קנה עירוב » (שו״ע או״ח שס״ט:א): the article makes an exchange, chalifin (Mishnah Berurah, ס״ק ד).
↓
Through another, or at the market → « וכן אם זיכה לו הנחתום ע״י אחר או שקנה במעה שנתן לו לחם מן השוק קנה עירוב » (שו״ע או״ח שס״ט:א). The Mishnah Berurah reads the acquisition through another as the case where the baker named him (ס״ק ה), and reports that some Acharonim disagree (ס״ק ו); at the market, the baker became like his agent (ס״ק ז).
↓
The coin to a private householder → « ואם נתן מעה לבעל הבי׳ ואמר לו זכה לי בעירוב קנה עירוב » (שו״ע או״ח שס״ט:א): a householder is not in the habit of selling what is his (Mishnah Berurah, ס״ק ח).
4. Decision tree — has the one who pays for his share acquired the eruv?
Q0: Was the coin given to the baker? If it was given to a private householder, go straight to the end of the seif, at the bottom of the tree: Q1 to Q3 concern only the baker, in the order of the seif.
↓ to the baker
Starting point (beginning of the seif): a coin given to the baker with “acquire for me” does not make the eruv, even if he was counted among everyone (seif א; Mishnah Berurah, ס״ק ב). The seif then names what does.
↓
Q1: Did he tell the baker “make the eruv for me”?
↓ YES → he has acquired the eruv (seif א; Mishnah Berurah, ס״ק ג); NO ↓
Q2: Having said “acquire for me”, did he hand over an article as a kinyan?
↓ YES → he has acquired the eruv (seif א; Mishnah Berurah, ס״ק ד); NO ↓
Q3: Did the baker have it acquired for him through another, naming him (this is how the Mishnah Berurah reads the seif, ס״ק ה), or buy him bread at the market with the coin?
↓ YES → he has acquired the eruv (seif א; Mishnah Berurah, ס״ק ה and ז; on the acquisition through another, some Acharonim disagree, ס״ק ו); NO → the rule at the start of the seif: it is not an eruv (seif א; Mishnah Berurah, ס״ק ב); if the baker had it acquired for him through another without naming him, the Biur Halachah leaves the question open (Pitfall 4), and the Shulchan Aruch HaRav writes that, when the loaf was transferred to all together through another person, as an outright gift, he has no share in the eruv, unless the baker had in mind to make the zocheh this man's agent too (369:1, section 5) — consult your Rav
End of the seif (if, at Q0, the coin was given to a private householder): with “acquire for me”, he has acquired the eruv (seif א; Mishnah Berurah, ס״ק ח).
→ The Mishnah Berurah reports a disagreement on the acquisition through another (ס״ק ו); the Taz does not read the start of the seif as it does (ס״ק א); and the Biur Halachah leaves in question the boundary between the start of the seif and the clause « וכן אם זיכה לו הנחתום ע״י אחר » (שו״ע או״ח שס״ט:א), « וע״כ צ״ע לדינא » (ביאור הלכה שס״ט): consult your Rav.
5. The Mechaber and the Alter Rebbe — where their texts differ
The Shulchan Aruch of the Alter Rebbe also has a single seif for this siman. Level 4 gives its full text and the comparison; here are points where his text differs from the Mechaber's seif. These points are not unique to the Rav for all that: most of these reasons can already be read in the Tur, in Rashi, and in the Magen Avraham and the Taz, which Level 4 quotes at each point. The rows follow the order of the Mechaber's seif; in the Rav's text, the parenthesis quoted in the row “The baker, through another” belongs to his first case and comes before “make the eruv for me”.
| Point | Mechaber (seif א) | Shulchan Aruch HaRav (369:1) |
|---|---|---|
| Why the coin given to the baker does not acquire | The seif states the rule without giving its reason: « זכה לי בעירוב שיהא לי חלק עמהם בשביל מעה זו אינו עירוב » (שו״ע או״ח שס״ט:א) | « שֶׁמָּעוֹת אֵינָן קוֹנוֹת עַד שֶׁיִּמְשׁוֹךְ » (שו״ע הרב שס״ט:א); and, for the baker who had the loaf acquired for all the residents together, through another person, as an outright gift: « אֶלָּא דַּעַת הַנַּחְתּוֹם הוּא שֶׁזֶּה יֵשׁ לוֹ כְּבָר זְכוּת בְּכִכָּר זֶה בִּשְׁבִיל הַמָּעָה שֶׁנָּתַן לוֹ » (שו״ע הרב שס״ט:א). These are the Tur's reasons, which the Magen Avraham (ס״ק א) takes up; Rashi already writes the first, « שאין מעות קונות עד שימשוך » (רש״י עירובין פ״א ע״א): see Level 4; on the intention Rashi speaks of, see Level 2, section 3 |
| “Make the eruv for me” | « אבל אם אמר לו ערב לי קנה עירוב » (שו״ע או״ח שס״ט:א), without the reason; the Tur gives it, and the Magen Avraham repeats it (ס״ק ב, see Level 4) | « קָנָה עֵרוּב בְּכָל עִנְיָן אִם זִכָּה לְכָל בְּנֵי הֶחָצֵר כֻּלָּם בִּכְלָל » (שו״ע הרב שס״ט:א); and « שֶׁהֲרֵי עֲשָׂאוֹ שָׁלִיחַ לְעָרֵב לוֹ בְּעִנְיָן שֶׁיּוֹעִיל » (שו״ע הרב שס״ט:א) — it is as if he had asked the baker to have it acquired for him through another, « וְלֹא יִזְכֶּה בְּמָעָה בִּלְבַדָּהּ » (שו״ע הרב שס״ט:א) |
| The baker, through another | « וכן אם זיכה לו הנחתום ע״י אחר… קנה עירוב » (שו״ע או״ח שס״ט:א); the seif does not mention the baker's intention. The Mishnah Berurah reads this clause as the case where he named him (ס״ק ה) | The Rav's text does not repeat this clause for the baker; for a transfer made to all together through another person, as an outright gift, he writes that the payer has no share, then, in parentheses, the baker's intention that makes the exception: « אֲבָל אִם יֵשׁ בְּדַעְתּוֹ שֶׁיִּהְיֶה הַזּוֹכֶה שָׁלִיחַ לְזֶה כְּמוֹ לִשְׁאָר בְּנֵי הֶחָצֵר — קָנָה עֵרוּב » (שו״ע הרב שס״ט:א); the seif, as the Taz explains it, holds acquisition through another valid without setting this condition (ס״ק א), and the Biur Halachah attributes to the Beis Yosef and the Taz that it is effective even if the baker did not name him, before concluding « וע״כ צ״ע לדינא » (ביאור הלכה שס״ט); Tosafos (Eruvin 81a; the Taz cites their view, ס״ק ד) wrote, against Rashi's explanation on the Mishnah, that the baker's intention does not suffice — concluding that Rashi's wording a little further on supports them —, the Taz defending them against the Rosh; the Beis Yosef traces the Tur's sentence, which the seif repeats, to the Rosh and not to Tosafos, and the Taz writes that the Rosh ruled so, and so did the Tur and the Shulchan Aruch (ס״ק ד; Level 4). Whether this parenthesis answers the Mechaber's clause, this page does not decide: consult your Rav |
| The coin to a private householder | « ואם נתן מעה לבעל הבי׳ ואמר לו זכה לי בעירוב קנה עירוב » (שו״ע או״ח שס״ט:א), without the reason; the Tur gives it, and the Magen Avraham repeats it (ס״ק ג, see Level 4) | « לְפִי שֶׁאֵין דֶּרֶךְ בַּעַל הַבַּיִת לִמְכּוֹר פַּת מִשֶּׁלּוֹ » (שו״ע הרב שס״ט:א); and, by default: « וַחֲזָקָה שָׁלִיחַ עוֹשֶׂה שְׁלִיחוּתוֹ, וּמִן הַסְּתָם קָנָה לוֹ וְזָכָה בִּשְׁבִילוֹ, אוֹ זִכָּה לוֹ עַל יְדֵי אַחֵר מִשֶּׁלּוֹ » (שו״ע הרב שס״ט:א). The reason and the presumption are, give or take a few words, the Tur's: the Rav also names the bread, « לִמְכּוֹר פַּת מִשֶּׁלּוֹ » (שו״ע הרב שס״ט:א) and « בְּמָעוֹתָיו פַּת מִן הַשּׁוּק » (שו״ע הרב שס״ט:א), which the Tur, the Taz and the Magen Avraham do not name for the householder; Rashi already named the loaves for the custom of selling, and the Rambam the bread for the purchase (Level 4); the last clause is found neither in the Tur, nor in the Magen Avraham, nor in the Taz, but the Mishnah Berurah writes its second branch (ס״ק ח; Level 4) |
| The presumption about the agent | The text of the seif does not mention it | The Rav writes it for “make the eruv for me” and for the private householder: וַחֲזָקָה שָׁלִיחַ עוֹשֶׂה שְׁלִיחוּתוֹ (369:1). It is already found in Rashi for “make the eruv for me”, and in the Tur and the Taz (ס״ק ה) for the private householder (Level 2, sections 6 and 9; Level 4) |
6. Mnemonic עכב
Three terms of the seif, in the order in which it introduces them, form עכב — three of the ways by which one who has paid acquires the eruv:
ע — ערב לי: he made the baker his agent (seif א; Mishnah Berurah, ס״ק ג).
כ — כלי: with “acquire for me”, the article handed over as a kinyan acquires (seif א; Mishnah Berurah, ס״ק ד).
ב — בעל הבי׳: the coin given to a private householder, saying “acquire for me [a share] in the eruv”, acquires (seif א; Mishnah Berurah, ס״ק ח).
Between כ and ב, the seif also names the acquisition through another and the bread bought at the market. And the coin alone, given to the baker with “acquire for me”, does not acquire (seif א). For halachah lema'aseh, consult your Rav.
7. Pitfalls to avoid
Pitfall 1: Thinking that having paid is enough. With the coin alone given to the baker and “acquire for me”, it is not an eruv (seif א). The reason: « שֶׁמָּעוֹת אֵינָן קוֹנוֹת עַד שֶׁיִּמְשׁוֹךְ » (שו״ע הרב שס״ט:א); the Mishnah Berurah writes it too, « דדוקא מעות אינן קונות עד שימשוך החפץ אבל אם מקנה לו כלי הוי חליפין » (משנה ברורה שס״ט ס״ק ד). The case where the baker counted him among all is Pitfall 2.
Pitfall 2: Thinking that being counted among everyone is always enough. In the case of the seif — the coin given to the baker with “acquire for me” — even if the baker made the eruv for everyone and « וזכה גם לזה עמהם » (שו״ע או״ח שס״ט:א), it is not an eruv for him (seif א). According to the Mishnah Berurah, he was included without being named, and, by default, the baker did not mean to give it to him as a gift but to act for his coin, and money does not acquire (ס״ק ב). The reverse is also wrong: with “make the eruv for me” (ס״ק ג) and with a private householder (ס״ק ח), the Mishnah Berurah writes that inclusion among everyone suffices. On the scope of this first case, see Pitfall 4.
Pitfall 3: Treating “acquire for me” and “make the eruv for me” as equivalent. The seif distinguishes them: « אבל אם אמר לו ערב לי קנה עירוב » (שו״ע או״ח שס״ט:א); these words make the baker an agent (Mishnah Berurah, ס״ק ג).
Pitfall 4: Taking as settled the boundary between the start of the seif, where the eruv made for everyone does not help him, and the clause at the end, « וכן אם זיכה לו הנחתום ע״י אחר » (שו״ע או״ח שס״ט:א), where he has acquired. The Mishnah Berurah distinguishes the start from the end by the name: at the end, « ר״ל שפרט שמו בהדיא ולא בסתמא עם אחרים » (משנה ברורה שס״ט ס״ק ה); it also reports « ויש מאחרונים שחולקין ע״ז » (משנה ברורה שס״ט ס״ק ו). The Taz reads the start differently: there the baker transfers by himself, « פי׳ הוא עצמו מזכה להם ולו אבל לא ע״י אחר » (ט״ז או״ח שס״ט ס״ק א). The Biur Halachah writes that, for the halachah, the Beis Yosef and the Taz hold that an acquisition made through another, even without naming him, is valid, but that they read it into the Tur, which cannot be read so; and he concludes « וע״כ צ״ע לדינא » (ביאור הלכה שס״ט). The Shulchan Aruch HaRav, who places the first case in a transfer made to all together through another person, as an outright gift, writes that the payer has no share in it, unless the baker had in mind to make the zocheh this man's agent too (369:1, section 5). Consult your Rav.
Pitfall 5: Extending the baker's rule to the private householder. For the householder the seif rules the other way: « ואם נתן מעה לבעל הבי׳ ואמר לו זכה לי בעירוב קנה עירוב » (שו״ע או״ח שס״ט:א); the Mishnah Berurah gives the reason (ס״ק ח).
Pitfall 6: Attributing to the Mechaber's seif the reasons for its rules. The seif states the rules; the reasons reported on this page come from the commentators — among them Rashi, Tosafos, the Rosh, the Tur, the Magen Avraham, the Taz, the Mishnah Berurah — and the Shulchan Aruch HaRav writes several of these reasons into the body of the law (369:1, see section 5).
8. Practical cases
These situations are applications by the site: the seif does not name them; each is tied to the part of the seif it involves.
| Situation | Analysis | Conduct |
|---|---|---|
| Paying the bakery in advance for one's share of the eruv bread | Application by the site, seif א: the seif's ruling on a coin given to the baker | With the coin alone and “acquire for me”, it is not an eruv; with “make the eruv for me”, or with an article handed over as a kinyan, he has acquired the eruv; and, even with the coin alone, he has acquired it if the baker then conferred it on him through another (naming him, according to the Mishnah Berurah, ס״ק ה; see the row where the baker confers one's share through a third party) or bought him bread at the market with the coin (ס״ק ז) (seif א). What one should say and hand over today: consult your Rav |
| The baker assures him that he counted the payer among the whole courtyard | Application by the site, seif א: « וזכה גם לזה עמהם » (שו״ע או״ח שס״ט:א); according to the Mishnah Berurah, if he handed over the coin with “acquire for me” and was included without being named, he has no share (ס״ק ב); with “make the eruv for me”, or with a private householder, inclusion among all suffices (ס״ק ג, ס״ק ח); the Taz reads this case differently (ס״ק א), and the Biur Halachah leaves the halachah in question | With the coin alone and “acquire for me”, the seif writes that it is not an eruv; the scope of this case is disputed (section 7, Pitfall 4). The Shulchan Aruch HaRav writes that, if the loaf was transferred to all together through another person, as an outright gift, he has no share, unless the baker had in mind to make the zocheh this man's agent too (369:1, section 5). Consult your Rav |
| The baker confers one's share through a third party | Application by the site, seif א: the acquisition through another; the Mishnah Berurah reads it as the case where he named him explicitly (ס״ק ה) | If he named him, he has acquired the eruv, according to the seif as the Mishnah Berurah reads it (ס״ק ה), which also reports that some Acharonim disagree (ס״ק ו); if he had handed over the coin with “acquire for me” and was included without being named: according to the Mishnah Berurah, he has no share (ס״ק ב); the Biur Halachah leaves the question open (Pitfall 4); the Shulchan Aruch HaRav writes that he has no share, unless the baker had in mind to make the zocheh this man's agent too (369:1, section 5); if he had said “make the eruv for me”, inclusion among all suffices (ס״ק ג). Consult your Rav |
| Giving money to a neighbor who prepares the eruv | Application by the site, seif א: the seif rules for the private householder, and the Mishnah Berurah gives the reason (ס״ק ח) | Whether the one receiving the money counts as a private householder or as a seller: consult your Rav |
9. Final synthesis table
| Element | Detail |
|---|---|
| Subject of the siman | How the eruv is transferred: has one who gives money for his share acquired it? |
| Place | Hilchos Eruvin, after siman 368 |
| Number of seifim | 1 (Mechaber, with no gloss of the Rema) — 1 also in the Shulchan Aruch HaRav |
| Mishnah Berurah | 8 ס״ק |
| Talmudic source | Eruvin 81a-b (the mishnah and Shmuel's distinctions), studied in Levels 1 and 2 |
| Golden rule | The coin alone, given to the baker with “acquire for me”, does not acquire; the other ways of the seif do (seif א) — acquisition through another: naming him, according to the Mishnah Berurah (ס״ק ה); the boundary is discussed: Pitfall 4 |
| Practical ruling | The seif writes each case; the boundary between its start and the acquisition through another is read in different ways (Mishnah Berurah, ס״ק ה; Taz, ס״ק א), the Biur Halachah leaves it in question (« וע״כ צ״ע לדינא » (ביאור הלכה שס״ט)), and the Mishnah Berurah reports a disagreement on the acquisition through another (ס״ק ו): consult your Rav |
10. The practical commandments of Siman שס״ט
For daily conduct
- The coin given to the baker with “acquire for me” does not make the eruv, even if he made the eruv for everyone and included him (seif א); the scope of this case is disputed (Taz, ס״ק א; Biur Halachah).
- “Make the eruv for me” makes the eruv (seif א).
- “Acquire for me” with an article handed over as a kinyan makes the eruv (seif א).
- If the baker had it acquired for him through another (naming him, according to the Mishnah Berurah, ס״ק ה), or bought him bread at the market with the coin, he has acquired the eruv (seif א); on the first way, the Mishnah Berurah reports a disagreement (ס״ק ו).
- The coin given to a private householder with “acquire for me” makes the eruv (seif א).
- The Shulchan Aruch HaRav writes that in the first case — a coin given to the baker with “acquire for me”, the loaf transferred to all together through another person, as an outright gift — the baker considers that the payer already has a right in the loaf through the coin, and does not make the zocheh the payer's agent; he concludes: « וְנִמְצָא שֶׁאֵין לוֹ חֵלֶק בָּעֵרוּב » (שו״ע הרב שס״ט:א); in parentheses, he writes that if the baker had in mind to make the zocheh this man's agent too, he has acquired the eruv (369:1); Tosafos wrote, against Rashi's explanation on the Mishnah, that this intention does not suffice, while concluding that Rashi's wording a little further on supports them (Tosafos, Eruvin 81a; their view is cited by the Taz, ס״ק ד), and the Rosh questions them (Taz, ס״ק ד); the seif, as the Taz explains it, holds acquisition through another valid without this condition (ס״ק א) — see section 5 and Level 4.
- In case of doubt: consult your Rav.
- In-depth pilpul — Level 2; Chabad shitah — Level 4.
📚 Recap of the study path
You have studied Siman שס״ט in 3 levels:
You have studied Siman שס״ט in 3 levels:
- 🌱 Level 1 — Base: the Mechaber's seif, with no gloss of the Rema, English translation, halachic concepts, the 8 ס״ק of the Mishnah Berurah
- ⚡ Level 2 — Lamdan: the sugya of Eruvin 81a-b, שיטות of the Rishonim, the chakirah on what the coin lacks
- ✨ Level 3 — Synthesis: axiom, mnemonic, decision tree, practical rulings