prithvi ke sthir manne par surya sapeksh rup se prithvi ka chakkar lagata hua pratit hota hai aur chandrama to prithvi ke charon or chakkar lagata hi rahta hai, isi karan surya aur chandrama kabhi vakri gati se bhraman karte hue pratit nahin hote hain. rahu evan ketu ke kalpanik katav bindu hain. chunki prithvi evan chandrama apni-apni kakshaon men nirdharit disha evan gati se bhraman karte hain islie yah bindu (rahu evan ketu) anya grahon ke viprit sadaiv vakri bhraman karte pratit hote hain. sabhi grah ghari ki sui ki viprit disha men surya ka chakkar lagate hain, kintu kabhi-kabhi prithvi se dekhne par inki gati viprit disha men (arthat dae. amit kumar ‘ram’ pashchim se purva) hona pratit hoti hai, jise grah ki vakri avastha kahte hain. prithvi aur surya ke madhya jab budh evan shukra ate hain to ve vakri hote hain.
anya grah (mangal, guru, shani, harshal, nepchyun, pluto) aur surya ke madhya jab prithvi a jati hai to sanbandhit grah vakri ho jate hanai. donon hi sthitiyon men sanbandhit grah prithvi ke nikat hone ke karan vakri gati se chalayman pratit hote hain. grahon ki gati evan kaksha nishchit hone ke karan pratyek grah ke vakri hone ka samay nishchit rahta hai jise talika men darshaya gaya hai. chunki grah jab bhi vakri hote hain, ve prithvi ke adhikatam samip hote hain. islie prithvi par unki kirnon ka prabhav sarvadhik parilakshit hota hai. astu, vakri grah apni prakriti ke anurup adhik faldayi ho jate hain. isilie jyotish men vakri grah ko ati balvan mana gaya hai. ‘‘krura vakra mahakruraah saumya vakra mahashubhaah’’ arthat vakri hone par krur grah ati krur fal dete hain tatha saumya grah atishubh fal dete hain. ’‘faldipika’ ke rachyita shri mantreshvar ka mat hai ki grah jab vakri hote hain to unhen cheshtabal prapt hota he.
cheshtabli grah niahsandeh rajya aur yash dete hain yadi ve bhav sanbandh se shubh hon, kintu yadi ve bhav sanbandh se ashubh hain to achcha fal nahin dete. vakri, anuvakri, vikal, mandatar evan mand ka cheshtabal kramshah 1, 1/2, 1/4, 1/8, 1/4, mana gaya hai. astu vakri grah sarvadhik cheshtabli hone se balvan hota hai. jyotish granth ‘uttar kalamrit’ ke ‘balsadhan khand’ ke 6the shlok ke anusar. vakri sarvochchabalah savakrashit madhyan balan tungabhe. vakri nichblah svanich bhavne vakri balan tungajam. uchchasthen yuvo'rddhaviryamiti chenniche tu shunyan balan. mitraiah papkhgaiah shubhe ripukhgairyukto'pi charddhan balam..
arthat vakri ka bal uske uchch hone ke saman samjhna chahie. koi grah jab kisi vakri grah ke sath ho, to usko 1/2 rupa (50pratisht) bal aur mil jata hai. yadi koi grah uchch parantu vakri ho to usko nich (bal shunya) samjhna chahie. grah yadi nich parantu vakri ho to apni uchch rashi men hone jaisa bali hota hai. uchch grah ke sath sthit grah 50 pratishat adhik bal pa jata hai. nich grah ke sath vidyaman grah shunya bal pata hai. koi grah jab kisi naisargik pap, parantu mitra athva naisargik mitra, parantu papi grah ke sath sthit ho to 1/2 rupa (50 pratisht) bal pata hai. jyotish shastra ke prasiddh granth ‘saravli’ ke anusar shubh grah vakri hokar ati balvan ho jate hain aur jatak ko rajya sukh dete hain, kintu pap grah vakri hone par jatak vyasni, dukhdayi aur vyarth ghumne vala hota hai.
jyotish granth ‘bhav manjri’ ke anusar yadi shubh grah uchch rashi men sthit hokar vakri ho to adhik shubh ho jata hai kintu krur grah vakri ho to mahakrur ho jata hai. shubh grah se aur adhik shubh fal milta hai tatha vakri papi grah se pap fal bhi adhik milta hai. vakri grah ke sanbandhit bhav se shubh-ashubh fal ke vishay men bhi acharyon men mataikya nahin hai. jyotish granth ‘saket nidhi’ ke anusar vakri grah ka prabhav apne karakatva bhav par bhi vishesh rup se parta hai arthat mangal vakri hone par apne tisre bhav, guru apne se pancham bhav, shukra apne se saptam bhav, budh chaithe sthan evan shani navam sthan sanbandhit fal vishesh rup se dete hain. ‘prashn prakash’ ke anusar mangal, budh, shukra grah bali hone par aur atichari hone par purva rashi ka fal dete hain, kintu shani aur guru jis rashi men sthit hon usi ka fal dete hain.
iske viprit jyotish granth ‘aranbhsiddha’ ke anusar vakri ya atichari hone par mangal 15 din tak, budh 10 din tak, guru ek mah tak, shukra 10 din tatha shani 5 mah age ki rashi ka fal dete hain aur uske bad apni rashi ka fal dete hain. kuch acharya yah bhi mante hain ki vakri grah ka shubh-ashubh bhav ka nishchay usse pahle bhav se sunishchit kiya jana chahie jahan vah sthit hai kyonki grah vakri hone par uski drishti viprit ho jati hai. vakri grah ke sanbandh men vyavharik rup se jo siddhant sucharu rup se pratipadit hote hain vah sankshep men nimnanusar hai:
1. chunki grah prithvi ke nikat hone se vakri hote hain islie vakri grah balshali hokar adhik prabhavi ho jate hain.
2. naisargik rup se saumya grah vakri hone par atishubh tatha krur grah vakri hone par mahakrur ho jate hain.
3. grah apni nich rashi ya nich navansh men ho aur vakri ho kintu ast nahin ho to use mahabli samjha jana chahie. iske viprit yadi koi grah uchch, mitra kshetri, svagrihi, vargottami hokar ast ho to use amavasya ke chandrama ki bhanti nirbal samjhna chahie.
4. chunki vakri avastha men grah ki gati samanya ke viprit hoti hai, islie is avastha men grah ka vyavhar asahaj (samanya avastha se hatkr) hota hai, vah apni dasha-antardasha men chaikane vale parinam bhi dete hain.
5. vakri grah ke naisargik svabhav men aur drirhta a jati hai kintu vyavhar men faldata ke rup men ashjta evan apratyashitta ka samavesh mukhya rup se hota hai.
6. vakri grahon ka prabhav chalit kundli ke pariprekshya men bhi vishleshit karna chahie. jatak ko milne vala shubhashubh fal janmakundli men nirmit anya karkon par bhi nirbhar hota hai. yah bat bhi aksar dekhne men ati hai ki yadi do ya adhik papi grah ek sath vakri hote hain to koi apriya ghatna vittiya bajar men ghatit hone ki prabal sanbhavna ban jati hai. yadi tin se adhik grah (saumya krur donon) ek sath vakri hote hain to koi bari durghatana vishva star par ghatit ho sakti hai.