✦ ❖ ✦

DAAT · LEVEL 4 — DAAT HARAV (CHABAD) & HALACHA LEMA'ASSE

שולחן ערוך · יורה דעה

Siman 184 — Separating One Onah Before the Period: Perishah, the Traveler's Pekidah, and the Pregnancy / Nursing Exemption

סימן קפ״ד · דעת הרב והלכה למעשה

פרישה סמוך לווסת ויסוד דיני הווסתות

שיטת הצמח צדק וחב״ד · פסק הבית יוסף והרמ״א · נושאי הכלים והפוסקים בזמננו

🕯️ דעת הרב · פסק הלכה ולמעשה 🕯️

✦ ❖ ✦

Daat HaRav (Chabad) & Halacha lema'asse

The shitah of the Tzemach Tzedek and Chabad on the וסתות and perishah,
then the halacha lema'asse of the nossei kelim and the contemporary poskim

Subject:
שולחן ערוך יורה דעה סימן קפ״ד (י״ב סעיפים)
פרישה סמוך לווסת: עונה אחת, הפוקד לפני דרך, פטור מעוברת ומניקה

Register:
Taharat haMishpacha is an intimate and weighty subject.
We expose the sugya and the shitot ; we never rule on a personal case.
For any application: consult your Rav (or a Chabad Rav / Dayan / a Yoetzet).

Writing and iyun:
הרב יוסף חיים סממה · DAAT

How to read this level. Siman 184 deals with perishah: at the time the וסת is expected, husband and wife separate for one עונה (from tashmish only), lest she see blood. The siman has twelve seifim and unfolds the whole system of וסתות (a fixed or non-fixed cycle, by day or by night), the law of one who sets out on a journey (יוצא לדרך) and must visit (פוקד) his wife, and the exemption of the pregnant and nursing woman (מעוברת ומניקה). This level has two parts. (1) Daat HaRav — the Chabad shitah: unlike kashrut, here there is a genuine Chabad halakhic tradition, whose authority of reference is the Tzemach Tzedek, and stringency in the וסתות is a recognized Chabad domain. (2) Halacha lema'asse: the general pesak (Beit Yossef, Rama, Shach, Taz, Sidrei Tahara, Chochmat Adam, Aruch haShulchan) and the contemporary pesak (Taharat haBayit, Shiurei Shevet haLevi, Badei haShulchan). We cite only real and attested positions ; where a specific Chabad ruling is not established with certainty, we present it at the level of principle. Every concrete application (lema'asse) concludes with the referral to your Rav (or a Chabad Rav / Dayan): this subject is never decided alone.

📑 תוכן העניינים

שורש הסימן — חזקת אורח בזמנו בא ופרישת עונה (י״ב סעיפים)
פסק המחבר והרמ״א — מסגרת דיני הווסתות והפרישה
שיטת הצמח צדק וחב״ד — דעת הרב על הווסתות והפרישה
וסתות דרבנן או דאורייתא — שורש המחלוקת (נודע ביהודה)
פרישת עונה — עונה אחת, יום או לילה, רק מתשמיש
מעוברת ומניקה — פטור הפרישה (משהוכר עוברה, כ״ד חדשים)
היוצא לדרך — מצות פקידה ודבר מצוה (סימן קפ״ד:י)
פסיקת הספרדים בזמננו — טהרת הבית, ילקוט יוסף
פסיקת האשכנזים — סדרי טהרה, ערוך השולחן, שיעורי שבט הלוי
מקרים מודרניים — מעקב הווסת, פקידה לפני דרך, בדיקות
סיכום מעשי וטבלאות — ולמעשה, שאל את רבך

📜 The Text of the Shulchan Aruch — The Opening (י״ב סעיפים)

רֹב הַנָּשִׁים יֵשׁ לָהֶם וְסָתוֹת (זְמַן קָבוּעַ לִרְאוֹת), כְּגוֹן מֵעֶשְׂרִים לְעֶשְׂרִים יוֹם אוֹ מִשְּׁלֹשִׁים לִשְׁלֹשִׁים יוֹם. וְכָל אִשָּׁה שֶׁיֵּשׁ לָהּ וֶסֶת קָבוּעַ — בָּא עָלֶיהָ שֶׁלֹּא בִּשְׁעַת וִסְתָּהּ וְאֵינָהּ צְרִיכָה בְּדִיקָה לִפְנֵי תַשְׁמִישׁ.

בִּשְׁעַת וִסְתָּהּ צָרִיךְ לִפְרֹשׁ מִמֶּנָּה עוֹנָה אַחַת, וְלֹא מִשְּׁאָר קְרִיבוֹת אֶלָּא מִתַּשְׁמִישׁ בִּלְבַד ; אִם הוּא בַּיּוֹם — פּוֹרֵשׁ אוֹתוֹ הַיּוֹם כֻּלּוֹ, וְאִם בַּלַּיְלָה — פּוֹרֵשׁ כָּל הַלַּיְלָה.

The principle. Most women have a וסת (a fixed-time cycle), for example from twenty to twenty days or from thirty to thirty days. A woman who has a fixed cycle (וסת קבוע): outside the time of her וסת, her husband may have relations with her without a bedika before tashmish (Rambam).

At the time of the וסת, one must separate from her for one עונה, and only from tashmish (not from other expressions of affection) ; if the וסת is by day → he separates the whole day ; if by night → the whole night. Rama: outside of tashmish, "whoever examines more, this is praiseworthy."

— Shulchan Aruch, Yoreh De'ah 184:1-2 (of י״ב seifim) · Talmudic basis: נדה (the וסתות, "the period comes in its time") · Sefaria YD 184:1

1. שורש הסימן — Akirah, the Onah, and the Vesatot

The foundation. Siman 184 rests on a presumption: אורח בזמנו בא — "the period comes in its time." When the וסת approaches, we presume blood might come ; we therefore take a precaution. (1) The precaution is not a prohibition of niddah (she has not seen blood) but a פרישה — a separation. (2) It applies only to one עונה (a day OR a night, never both for an ordinary וסת) and to tashmish alone. (3) The siman ties this to the system of וסתות: a fixed (קבוע) or non-fixed (לא קבוע) cycle, a cycle bound to days (תלוי בימים) or to a change of the body (cf. siman 189).

Perishah ≠ harchakot (a structuring distinction). Two regimes must be carefully distinguished. Here, at the time of the וסת, only tashmish is forbidden: "and not from other expressions of closeness, but from tashmish alone." The הרחקות (the distancings of the niddah herself — not touching, etc.) belong to a separate subject (siman 195), and apply only once the woman is actually a niddah. The perishah of the וסת is purely preventive: chibuk and nishuk remain permitted (Beit Yossef), though "one who is stringent, a blessing will come upon him."

Onah — day or night, and the mechanics of the separation

The עונה is a half-day: the day (from sunrise to sunset) or the night. If the וסת falls by day, one separates that whole day, even if the וסת is at its end, and is permitted immediately the following night ; if by night, one separates the whole night. The Taz (s.k. 2) discusses the extent of the perishah (one single עונה, not the day and the night). The Rama clarifies that all this applies only to the וסת התלוי בימים, not to the וסת bound to a change of the body (cf. siman 189).

2. פסק המחבר והרמ״א — The Map of the Siman

Siman 184 has twelve seifim. The Mehaber sets the principle (וסת → perishah of one עונה from tashmish only) then unfolds the cases (גדולה / קטנה / זקנה ; sunrise ; a וסת over 2-3 days ; מעוברת ומניקה ; the hidden woman ; the other women ; the traveler ; וסת לימים). The Rama (הגה) adds decisive points. Here is the map.

Seif	Concept	Ruling (anchored in the text)
1	Fixed cycle	A woman with a fixed cycle → relations outside the וסת without a bedika (Rambam). Rama: do not be stringent to examine before/after tashmish ; but outside tashmish, whoever examines more is praiseworthy.
2	Perishah of an עונה	At the וסת: separate one עונה (day OR night), from tashmish alone. Rama: only for the וסת bound to days (cf. 189) ; a cycle that advances/recedes 2-3 days → separate accordingly.
3	גדולה / קטנה / זקנה	The perishah falls only on the גדולה ; the קטנה (without simanim) and the זקנה (whose blood has ceased): no perishah until the וסת is established 3 times.
4-5	Sunrise	A sighting at sunrise, uncertain (before/after) → forbidden by day alone ; a sighting prolonged from day into night → night + day.
6	וסת over 2-3 days	A prolonged וסת (שופעת / מזלפת) → separate only the first עונה ; once it passes without a sighting → permitted.
7	מעוברת ומניקה	Pregnancy (once the embryo is recognized) / nursing (כ״ד חדשים, even if the child has died): no perishah at the וסת, and even during it she is permitted without a bedika (cf. 189).
8-9	Bedikot at the וסת	A woman hidden out of fear → she need not worry (Rama: bediavad). The other women: a bedika at the וסת ; if it passes without bedika or הרגשה → טהורה ; some say forbidden until she examines if she has a fixed cycle or it is day 30 (and so is the practice).
10	The traveler	One setting out on a journey must visit his wife (פוקד אשתו), even near the וסת. Rama: even tashmish is permitted (the וסתות are deRabbanan, "where there is a mitzvah they did not decree") ; a journey for a mitzvah → no pekidah.
11-12	וסת לימים	At the וסת: forbidden until he asks her (ישאלנה) ; no fixed cycle → day 30 is equivalent ; a day-bound cycle + a body-bound one → she is concerned for the average onah (30 days, cf. 189).

כלל הפסק של הסימן :
בִּשְׁעַת הוסת פּוֹרֵשׁ עונה אחת מִן התשמיש בִּלְבַד (לֹא שְׁאָר קְרִיבוֹת). הַיּוֹצֵא לְדֶרֶךְ פּוֹקֵד אֶת אִשְׁתּוֹ אַף סָמוּךְ לַוֶּסֶת (בִּמְקוֹם מִצְוָה לֹא גָזְרוּ). וּמְעוּבֶּרֶת וּמְנִיקָה — אֵין צְרִיכוֹת פְּרִישָׁה, וַאֲפִלּוּ בְּתוֹךְ וִסְתָּן מֻתֶּרֶת בְּלֹא בְדִיקָה. וְכָל פְּרָטֵי הַווְסָתוֹת — לְקַמָּן סִימָן קפ״ט.

3. שיטת הצמח צדק וחב״ד — Daat HaRav

Note on method (important). This part presents the Chabad halakhic approach to the וסתות and perishah. Unlike kashrut, here there is a genuine tradition of Chabad pesak. We present it at the level of principle and of the authorities ; we attribute to the Tzemach Tzedek and to no Rebbe any specific ruling, responsum number, or minhag that we could not verify. For the detail of a case, the Chabad practice is to turn to a Chabad Rav or a Dayan.

The Tzemach Tzedek — Chabad's authority of reference on Niddah

The Tzemach Tzedek — Rabbi Menachem Mendel Schneersohn (1789-1866), the third Rebbe of Lubavitch and grandson of the Admur HaZaken — is the foremost posek of Chabad, in particular in Taharat haMishpacha. His collection of responsa and pisqei dinim (the Shut Tzemach Tzedek) covers Yoreh De'ah and the laws of Niddah extensively, and it is to him that the Chabad tradition turns first for these questions. At the level of principle, the Chabad school is characterized by great stringency in Taharat haMishpacha, and precision in tracking the וסתות and in the perishah is a recognized domain of care.

Daat HaRav and the heart of the siman. On the very bedrock of this siman — the פרישה of an עונה at the time of the וסת, the tracking of the וסתות, the פוקד before a journey — the Chabad approach does not depart from the framework of the Shulchan Aruch and the Rama. Its distinctiveness shows in the rigor of the calculation and tracking of the וסתות and the care given to the perishah — matters of practical detail, verified with a Chabad Rav. We attribute to it no specific provision (duration, count, exemptions) that is not attested.

Lema'asse (Daat HaRav). According to the Chabad tradition, in these matters one follows the Tzemach Tzedek and the pisqei dinim transmitted in Chabad, with the rigor proper to the school in tracking the וסתות. For applying a real case (the calculation of the perishah, a journey, the pregnancy or nursing exemption), consult your Rav (or a Chabad Rav / Dayan): this level presents the principle, it does not decide your situation.

4. וסתות דרבנן או דאורייתא — The Great Machloket

Vesatot deRabbanan (Pitchei Teshuva, in the name of the Noda BiYehuda). The great debate of the Rishonim and Acharonim concerns the status of the וסתות: are they דאורייתא or דרבנן? The Noda BiYehuda (brought in the PT) teaches that the וסתות are deRabbanan with respect to the presumption (the concern that she may have seen) — but that the חזקת טהרה (presumption of purity) remains as long as she has not seen and examined. Several practical נפקא מינה depend on this point.

The נפקא מינה of the debate

The traveler's pekidah: because the וסתות are deRabbanan, במקום מצוה לא גזרו — where there is a mitzvah they did not decree the prohibition (Taz s.k. 14), hence the permission of tashmish for the traveler.
Chibuk and nishuk: only the perishah of tashmish is required ; other expressions of affection remain permitted (Taz s.k. 3).
The bedika after the fact: the חזקת טהרה explains why, once the וסת has passed without הרגשה or a sighting, the woman is טהורה without a bedika in many cases (cf. seif 9).

Lema'asse (status of the וסתות). Retain that the perishah of the וסת is a precaution (וסתות דרבנן per the Noda BiYehuda), tied to the חזקת טהרה. But the application of these presumptions to a real case — classifying a journey as a mitzvah, the bearing of a missed bedika — is not decided alone. Consult your Rav (or a Chabad Rav / Dayan).

5. פרישת עונה — One Onah, From Tashmish Alone

אִם הוּא בַּיּוֹם פּוֹרֵשׁ מִמֶּנָּה אוֹתוֹ הַיּוֹם כֻּלּוֹ אֲפִלּוּ אִם הַוֶּסֶת בְּסוֹפוֹ, וּמֻתָּר מִיָּד בַּלַּיְלָה שֶׁלְּאַחֲרָיו... וְכֵן הַדִּין אִם הוּא בַּלַּיְלָה פּוֹרֵשׁ כָּל הַלַּיְלָה.

— שולחן ערוך יו״ד קפ״ד:ב

The extent of the perishah (Taz s.k. 2). The perishah is measured in עונות: one single עונה — the day or the night on which the וסת is expected — and not the day and the night (Taz). This is a precise economy: one separates for the half-day concerned, and is permitted immediately the following עונה. The Rama adds two limits: (1) this applies only to the וסת התלוי בימים ; (2) a woman whose וסת advances or recedes by two or three days must separate on those days (Hagahot Maimoniyot).

A וסת over several days (seif 6)

If the וסת lasts two or three days (שופעת or מזלפת), the woman separates only the first עונה of the וסת ; once that עונה passes without a sighting, she is permitted. This is a direct application of the principle "one single עונה": the perishah targets the expected moment of the sighting, not the whole potential duration. The detail (which עונה counts as the first, how the וסת is established) belongs to the laws of the וסתות (siman 189).

Lema'asse (the perishah calculation). The rule: one עונה (day or night) of separation from tashmish alone, at the expected moment of the וסת. But determining which עונה, tracking a fixed or non-fixed cycle, handling a cycle that advances or a וסת over several days — all this requires careful tracking (a journal / a Taharat haMishpacha app) and a Rav's decision. Consult your Rav (or a Chabad Rav / Dayan / a qualified Yoetzet).

6. מעוברת ומניקה — The Exemption from Perishah

אִם הִגִּיעַ וִסְתָּהּ בִּימֵי עִבּוּרָהּ מִשֶּׁהֻכַּר עֻבָּרָהּ, אוֹ בִּימֵי מְנִיקָתָהּ שֶׁהֵם כ״ד חֳדָשִׁים מִשֶּׁנּוֹלַד הַוָּלָד אֲפִלּוּ מֵת הַוָּלָד — אֵין צְרִיכָה לִפְרֹשׁ סָמוּךְ לְוִסְתָּהּ, וַאֲפִלּוּ בְּתוֹךְ וִסְתָּהּ מֻתֶּרֶת בְּלֹא בְדִיקָה.

— שולחן ערוך יו״ד קפ״ד:ז · ועיין סוף סימן קפ״ט

The reason for the exemption (Taz s.k. 10). Why are the pregnant woman (from the moment the embryo is recognized — משהוכר עוברה) and the nursing woman (for כ״ד חדשים, even if the child has died) exempt from perishah, and even permitted during the וסת without a bedika? Because in these periods אין דמים מצויין — blood is not usual (the body is turned toward pregnancy / nursing) ; the Taz mentions that אבריה מתפרקין ("her limbs come apart"). The presumption of a sighting, the basis of the perishah, therefore falls away.

Chodesh ha-Ibbur — Shach vs Kreti uPleti (PT s.k. 13)

Several points are debated. (1) The כ״ד חדשים of nursing apply even if the child has died or is not nursed (the body remains, for a time, in a nursing disposition). (2) The chodesh ha-ibbur (the first month, before the embryo is recognized) is the subject of a machloket between the Shach and the Kreti uPleti (brought in the Pitchei Teshuva). These distinctions are delicate and very practical today (medical follow-up, early pregnancy, the end of nursing).

Lema'asse (pregnancy and nursing). The general rule: from the moment the embryo is recognized, and during the כ״ד חדשים of nursing, there is no perishah at the וסת. But when exactly this exemption begins and ends (recognition of the embryo, counting the 24 months, chodesh ha-ibbur, the return of the cycle) varies with the situation and the views — a very practical subject not to be decided alone. Consult your Rav (or a Chabad Rav / Dayan / a qualified Yoetzet).

7. היוצא לדרך — The Mitzvah of Pekidah

הָרוֹצֶה לָצֵאת לַדֶּרֶךְ צָרִיךְ לִפְקֹד אִשְׁתּוֹ אֲפִלּוּ סָמוּךְ לְוִסְתָּהּ. הגה: וַאֲפִלּוּ בְּתַשְׁמִישׁ שָׁרֵי... וְאִם הוֹלֵךְ לִדְבַר מִצְוָה אֵין צָרִיךְ לִפְקֹד אִשְׁתּוֹ.

— שולחן ערוך ורמ״א יו״ד קפ״ד:י

Where there is a mitzvah they did not decree (Taz s.k. 14). One who sets out on a journey must פוקד אשתו ("visit" his wife) even near the וסת. The Rama, in the name of Rashi, the Raavad, the Rashba, and Rabbenu Yerucham, goes further: even tashmish is permitted — for since the וסתות are deRabbanan, במקום מצוה לא גזרו (here, the pekidah before the separation). The Taz (s.k. 15) notes that one who wishes to be stringent suffices with דברי ריצוי (words of affection) — a blessing will come upon him.

The limits of the pekidah

A journey for a mitzvah: if he sets out himself for a dvar mitzvah, there is no pekidah (Hagahot Maimoniyot) — the mitzvah of the journey takes precedence.
All closeness except tashmish: apart from the traveler's case, recall that only the perishah of tashmish applies ; other expressions of affection remain permitted.
A niddah wife who will immerse: some say that if she is a niddah and immerses within the עונה, he must wait (Nimukei Yosef) — a point of iyun.

Lema'asse (the traveler's pekidah). The principle: there is a mitzvah of pekidah before departing, even near the וסת, but it has limits (a journey for a mitzvah, a niddah wife, etc.). Whether a given journey grants this, and how to conduct oneself concretely, belongs to a Rav who knows the situation. Consult your Rav (or a Chabad Rav / Dayan).

8. פסיקת הספרדים בזמננו — The Contemporary Sephardic Pesak

The contemporary Sephardic pesak (the school of Rav Ovadia Yossef) sets out from the Beit Yossef and the Shach. The practical reference is the Taharat haBayit of Rav Ovadia Yossef (and its abridgment Yalkut Yossef — Taharat haBayit, by Rav Yitzhak Yossef), which expounds in detail the foundations of this siman: the perishah of one עונה at the time of the וסת, the status of the וסתות (deRabbanan), the mitzvah of pekidah for the traveler, and the exemption of the מעוברת ומניקה. The spirit of this school tends to rely fully on the חזקת טהרה and on the deRabbanan character of the וסתות.

9. פסיקת האשכנזים — The Ashkenazi Pesak

Point of the siman	Sephardic orientation (to be verified)
פרישת עונה	One עונה (day / night) of separation from tashmish alone at the וסת ; tracking a fixed / non-fixed cycle. See Taharat haBayit / Yalkut Yossef.
פוקד / יוצא לדרך	Mitzvah of pekidah even near the וסת (deRabbanan, "where there is a mitzvah") ; limits for a journey of mitzvah.
מעוברת ומניקה	Exemption from perishah (once the embryo is recognized, כ״ד חדשים) ; the precise start/end to be confirmed.

The Ashkenazi pesak sets out from the Rama, the Shach, and the Taz, then from the key commentary of Niddah, the Sidrei Tahara, and the codifiers: the Chochmat Adam (and his Binat Adam) and the Aruch haShulchan (Yoreh De'ah), who treated the laws of the וסתות at length. For the twentieth century, the major practical reference is the Shiurei Shevet haLevi of Rav Shmuel Wozner (on the laws of Niddah), often accompanied by the Badei haShulchan (the reference commentary on the laws of Niddah). All develop the same axes: the perishah of an עונה, the tracking of the וסתות, pekidah, the exemption of the מעוברת ומניקה.

Point of the siman	Ashkenazi orientation (to be verified)
פרישת עונה	One עונה from tashmish alone ; the Sidrei Tahara and Shiurei Shevet haLevi refine its application (וסת התלוי בימים).
וסתות דרבנן	A deRabbanan status (Noda BiYehuda) ; נפקא מינה for the pekidah and the bedika ; the Aruch haShulchan details its rules.
בדיקות	A bedika at the וסת ; "whoever examines more is praiseworthy" outside tashmish ; some say forbidden until she examines if she has a fixed cycle (and so is the practice).

Chabad within the pesak

For Chabad practice on this bedrock, one turns to the Tzemach Tzedek (whose Shut covers the laws of Niddah extensively) and to the rulings transmitted within Chabad, with the rigor proper to the school in tracking the וסתות and in the perishah. We attribute no specific ruling that is not verifiable ; for the detail, one turns to a Chabad Rav or a Dayan.

10. מקרים מודרניים — Today's Practice (with Sobriety)

How siman 184 illuminates practice. Four concepts of the siman situate real cases: (1) פרישת עונה — the calculation of the עונה to separate ; (2) וסת קבוע / לא קבוע — tracking the cycle ; (3) פוקד / יוצא לדרך — the pekidah before a journey ; (4) מעוברת ומניקה — the exemption. All that follows is presented at the level of principle ; nothing is decided here.

Situation	Concept of the siman	Orientation (to be confirmed with the Rav)
Calculating the עונה to separate (fixed or non-fixed cycle)	פרישת עונה	One עונה (day / night) from tashmish alone at the expected moment ; tracking (a journal / an app) is essential. The exact calculation belongs to the Rav and to the laws of siman 189.
A journey is planned near the וסת	פוקד / יוצא לדרך	Mitzvah of pekidah even near the וסת ("where there is a mitzvah they did not decree") ; limits for a journey of mitzvah. The concrete conduct belongs to the Rav.
Recognized pregnancy / nursing (up to 24 months)	מעוברת ומניקה	Exemption from perishah, and even permitted during the וסת without a bedika ; the exact start/end (recognition of the embryo, 24 months, return of the cycle) is decided with the Rav.
Bedikot at the time of the וסת	בדיקות	A bedika at the וסת ; "whoever examines more is praiseworthy" outside tashmish ; the exact regime (fixed cycle, day 30) belongs to siman 189 and the Rav.

Lema'asse. These situations are intimate and touch a weighty subject (Taharat haMishpacha). They blend factual questions — what is the וסת, when does the עונה begin, is the journey a mitzvah, is the embryo recognized — that only a posek can decide knowing your situation. The practical rule: do not decide alone, and consult your Rav (or a Chabad Rav / Dayan / a qualified Yoetzet).

11. סיכום מעשי — Summary and Tables

טבלה — the axes of the siman, in practice

טבלה — who says what (nossei kelim of the siman)

טבלה — Daat HaRav and contemporary streams (to be verified)

Concept	In substance	Reference
פרישת עונה	One עונה (day / night) of separation from tashmish alone at the וסת	Taz s.k. 2 ; וסת התלוי בימים (cf. siman 189)
וסת קבוע / לא קבוע	Tracking the cycle ; perishah by the type of וסת	Rama (seif 2) ; details in siman 189
וסתות דרבנן	A deRabbanan precaution ; the חזקת טהרה remains	Noda BiYehuda (PT s.k. 3)
פוקד / יוצא לדרך	Mitzvah of pekidah even near the וסת ; even tashmish (Rama)	Taz s.k. 14-15 ; seif 10
מעוברת ומניקה	No perishah (once the embryo is recognized ; כ״ד חדשים)	Taz s.k. 10 ; PT s.k. 13 ; cf. siman 189
בדיקות	A bedika at the וסת ; whoever examines more is praiseworthy outside tashmish	Rama (seifim 1, 9) ; cf. siman 189

Posek	Decisive contribution (anchored in the corpus)
Mehaber	The principle: a fixed cycle → relations outside the וסת without a bedika ; at the וסת → perishah of one עונה from tashmish alone ; the traveler visits his wife ; the מעוברת ומניקה are exempt.
Rama (הגה)	Perishah only for the וסת bound to days ; pekidah even in tashmish ("where there is a mitzvah they did not decree") ; a journey of mitzvah → no pekidah ; whoever examines more is praiseworthy.
Shach (Siftei Kohen)	s.k. 1: "from twenty to twenty" (or 25, or 30) — the amplitude of the cycle ; positions on the chodesh ha-ibbur (via PT).
Taz (Turei Zahav)	s.k. 2 (one עונה) ; s.k. 3 (chibuk and nishuk permitted) ; s.k. 10 (reason for מעוברת/מניקה: "her limbs come apart") ; s.k. 14-15 (the traveler: deRabbanan, words of affection).
Pitchei Teshuva	s.k. 3 (Noda BiYehuda: deRabbanan, חזקת טהרה) ; s.k. 5 (Radbaz: chibuk and nishuk permitted) ; s.k. 13 (כ״ד חדשים, chodesh ha-ibbur — Shach vs Kreti uPleti) ; s.k. 17 (moch dachuk).

Chabad (Daat HaRav): the Tzemach Tzedek (Rabbi Menachem Mendel Schneersohn, 3rd Rebbe of Lubavitch) is Chabad's foremost posek on Niddah ; his Shut covers the laws of Niddah. The Chabad school is characterized by stringency in tracking the וסתות and in the perishah. For the detail of a case → Chabad Rav / Dayan. (No specific ruling is attributed here without a source.)

Sefaria links (text and nossei kelim)

👈 הלכה למעשה — the golden rule of this level

In substance, retain the four axes: פרישת עונה (one עונה from tashmish alone at the וסת), וסת קבוע / לא קבוע (the tracking), פוקד / יוצא לדרך (the mitzvah of pekidah), מעוברת ומניקה (the exemption).
Daat HaRav (Chabad): one follows the Tzemach Tzedek and the pisqei dinim of Chabad, with the school's rigor in tracking the וסתות ; the detail is verified with a Chabad Rav / Dayan.
Halacha lema'asse: Beit Yossef, Rama, Shach, Taz, Sidrei Tahara, Chochmat Adam, Aruch haShulchan, and the contemporary pesak (Taharat haBayit, Shiurei Shevet haLevi, Badei haShulchan) — all on these same axes.
And for any real case — the perishah calculation, a journey, the pregnancy or nursing exemption, the bedikot — halacha lema'asse goes through your Rav (or a Chabad Rav / Dayan / a qualified Yoetzet).