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tokens: conclusion that for positive (negative) helicity the apex of a filament rotates clockwise (counterclockwise). But the filament is believed to be associated with a flux rope taking on an S shape that is opposite to the corresponding sigmoid, the latter of which represents a current layer wrapping around the flux rope (Titov Démoulin 1999 ; Kliem et al. 2004 ). Green et al. ( 2007 ) hence rejected those models implying identical orientation for the sigmoid and the flux rope (e.g., Rust Kumar 1996 ; Kusano 2005 ). But in our sample and in the literature (e.g., Pevtsov 2002 ; Cheng et al. 2014 ; Zhou et al. 2017 ) often the cold filament and the hot sigmoid are co-spatial and have the similar S shape, suggesting that the filament is associated with a low-lying magnetic flux rope with its axis dipped in the middle (e.g., Zhou et al. 2017 ). Not all of these filament eruptions that are initiated make it to a full eruption; some of these cases expelled material flows back down to the Sun. Specifically, cases #4,#7,#9, and #11 expel material flows back down the legs of an erupting prominence and have no corresponding CME in the coronagraph observations, this subset of events are known as failed eruptions or confined eruptions, likely because of interactions with external magnetic field structures that may arrest the eruption or facilitate additional draining (McCauley et al. 2015 ; Zhou et al. 2019 ). This interaction may induce alternative rotation mechanism concerning the mutual orientation of the overlying arcade field and the erupting filament body (Isenberg Forbes 2007 ). For a given chirality of the erupting field, this mechanism yields the same rotation direction as the kink instability (e.g., Kliem et al. 2012 ). To summarize, by applying the method proposed by Chen et al. ( 2014 ) to determine filament chirality and using multiviewpoint observations to investigate the filament rotation, we established a strong relationship that during eruption sinistral/dextral filaments, which are located in the southern/northern hemisphere rotate clockwise/counterclockwise, when viewed from above, and corroborated a weak hemispheric preference that both the filament and related sigmoid exhibit a forward (reverse) S shape in the southern (northern) hemisphere. The one-to-one relationship between filament chirality and rotation direction may help understand the transformation of CMEs to interplanetary ejecta, and help predict statistically the latter’s characteristics, such as the axial orientation, the chirality of helical fields, and the strength and duration of southward magnetic field. As illustrated in Figure 4 , for both odd and even cycles, the rotation of eruptive active-region filaments makes their axes tilt toward the east–west direction. Such a statistical trend is already known for interplanetary magnetic clouds (Crooker 2000 ; Yurchyshyn et al. 2009 ), yet its connection with filament rotation has not been noticed. On the other hand, Figure 4