Saying Yishtabach immediately after Az Yashir:[1]

One is to recite Yishtabach immediately after Az Yashir, without making an interval in-between.[2] This applies even on Shabbos and Yom Tov.[3] [Thus, in the event that the Chazan is not yet up to Yishtabach, as commonly occurs on Shabbos and Yom Tov in which the Chazan recites from Shochan Ad with Chazanus, [and the individual is already has already reached the paragraph of Yishtabach[4]], then the individual is not to wait for the Chazan, and is to recite Yishtabach right away.[5]]

Waiting for a Minyan: [6] In the event that a Minyan is not yet available, and one must wait until the arrival of the tenth man, the individuals are not to wait between Az Yashir and Yishtabach but are rather to recite Yishtabach and then wait for the Minyan to arrive.[7] [Alternatively, they are to wait in the middle of Az Yashir and then complete Az Yashir and say Yishtabach when the Minyan arrives.] This however is with exception to the Chazan, as will be explained next.

Where is the Chazan to wait:[8] In the event that a Minyan is not yet available in Shul, the Chazan is to wait [between Az Yashir and] Yishtabach [until the arrival of the tenth man]. He is to wait silently, without saying anything, until the tenth man arrives, upon which he is to say Yishtabach and Kaddish. The Chazan may wait [between Az Yashir and Yishtabach] even for a period of thirty minutes[9], which is the amount of time it takes to complete the entire Pesukei Dezimra, from Baruch Sheamar until the end of Yishtabach.[10] [Practically, the Chazan is to wait by the end of Az Yashir, by Vehaya Hashem Limelech, and then recite from there aloud when the Minyan arrives.[11]]

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[1] M”A 53:4; M”B 53:9; Aruch Hashulchan 53:4; Ketzos Hashulchan 18:10; Darkei Chaim Veshalom 131; Piskeiy Teshuvos 53:4

[2] The reason: Seemingly this is because Yishtabach is the after blessing of Pesukei Dezimra and it hence must be proximated to the Psalms of Pesukei Dezimra. Alternatively, this is based on Kabala and is done in order to unify Hashem’s name of Shakaiy. [See Shalmei Tzibur]

[3] M”A and Poskim ibid

[4] However prior to reaching Yishtabach, such as by Shochen Ad, one may wait for the Chazan, and so is the custom.

[5] Aruch Hashulchan ibid

[6] M”A 53:4; M”B 53:9; Aruch Hashulchan 53:4; Ketzos Hashulchan 18:10; Darkei Chaim Veshalom 131; Piskeiy Teshuvos 53:4

[7] The reason: As one is to recite Yishtabach immediately after Az Yashir, without making an interval in-between. [Poskim ibid] Seemingly this is because Yishtabach is the after blessing of Pesukei Dezimra and it hence must be approximated to the Psalms of Pesukei Dezimra. Alternatively, this is based on Kabala and is done in order to unify Hashem’s name of Shakaiy and approximate the word Echad to Yishtabach. [See Shalmei Tzibur]

[8] Admur 53:3; Rama 53:3; M”A 53:5; Maharil Tefila 7; Chesed Lealafim 54:3; Kitzur SHU”A 15:1; Kaf Hachaim 55:5; Ketzos Hashulchan 18:10; Piskeiy Teshuvos 53:4

[9] Admur ibid; M”A ibid; Maharam Mintz 8

Other opinions: Some Poskim rule that the Chazan may wait up until a half hour before Yishtabach, however more than a half hour he may not wait and is rather to begin Yishtabach right away, and wait between Yishtavbach and Yotzer. [Kitzur SHU”A ibid]

[10] Admur ibid

The reason: Even if the Chazan waits for more than a half hour between Az Yashir and Yishtabach, nevertheless, he is not required to repeat Pesukei Dezimra, as a delay within Davening only requires a repetition if one made a delay due to Oness [i.e. in bathroom] and not if the delay was caused willingly, as explained in chapter 65:1. [Admur ibid]

[11] Yifei Laleiv 53:5; Mishmeres Shalom Minhagim 8; Piskeiy Teshuvos ibid

The reason: In order to approximate the end of Pesukei Dezimra to Yishtabach, as brought in Poskim in coming footnotes.